diff --git a/src/build-scripts/ci-test.bash b/src/build-scripts/ci-test.bash
index 89f3f5138b..79b1e502e8 100755
--- a/src/build-scripts/ci-test.bash
+++ b/src/build-scripts/ci-test.bash
@@ -47,6 +47,11 @@ echo "Default timeout ${CTEST_TEST_TIMEOUT}"
 echo "Test exclusions '${CTEST_EXCLUSIONS}'"
 echo "CTEST_ARGS '${CTEST_ARGS}'"
 
+# Adjustments to OPENIMAGEIO_OPTIONS
+# - limits:imagesize_MB=32768 forces the same limit regardless of physical
+#   memory size of the CI runner, for the sake of uniform error messages.
+export OPENIMAGEIO_OPTIONS="limits:imagesize_MB=32768,${OPENIMAGEIO_OPTIONS}"
+
 pushd build
 time ctest -C ${CMAKE_BUILD_TYPE} --force-new-ctest-process --output-on-failure \
     -E "${CTEST_EXCLUSIONS}" --timeout ${CTEST_TEST_TIMEOUT} ${CTEST_ARGS}
diff --git a/src/cineon.imageio/cineoninput.cpp b/src/cineon.imageio/cineoninput.cpp
index cf76059cba..f7704e4b42 100644
--- a/src/cineon.imageio/cineoninput.cpp
+++ b/src/cineon.imageio/cineoninput.cpp
@@ -7,6 +7,7 @@
 #include "libcineon/Cineon.h"
 
 #include <OpenImageIO/dassert.h>
+#include <OpenImageIO/filesystem.h>
 #include <OpenImageIO/imageio.h>
 #include <OpenImageIO/strutil.h>
 #include <OpenImageIO/typedesc.h>
@@ -130,7 +131,9 @@ CineonInput::open(const std::string& name, ImageSpec& newspec)
     m_spec = ImageSpec(m_cin.header.Width(), m_cin.header.Height(), nchannels,
                        typedesc);
 
-    if (!check_open(m_spec, { 0, 1 << 30, 0, 1 << 30, 0, 1, 0, 8 })) {
+    if (!check_open(m_spec, { 0, 1 << 30, 0, 1 << 30, 0, 1, 0, 8 })
+        || !check_compression_ratio(m_spec, Filesystem::file_size(name))) {
+        close();
         return false;
     }
 
diff --git a/src/cmake/testing.cmake b/src/cmake/testing.cmake
index 15605b35c2..8aa6ca0bf1 100644
--- a/src/cmake/testing.cmake
+++ b/src/cmake/testing.cmake
@@ -432,6 +432,9 @@ macro (oiio_add_all_tests)
     # Regression test (compiles its own helper and generates its own image)
     # for a partial edge-tile heap overflow in the OpenEXR readers.
     oiio_add_tests (openexr-partialtile)
+    # Self-contained decompression-bomb regression (ships its own tiny fixture);
+    # exercises both the C++ and C-API readers via the openexr:core attribute.
+    oiio_add_tests (openexr-bomb)
     # if (NOT DEFINED ENV{${PROJECT_NAME}_CI})
     #     oiio_add_tests (openexr-damaged
     #                     IMAGEDIR openexr-images
@@ -446,6 +449,8 @@ macro (oiio_add_all_tests)
     oiio_add_tests (png png-damaged
                     ENABLEVAR ENABLE_PNG
                     IMAGEDIR oiio-images/png)
+    # Self-contained decompression-bomb regression (ships its own tiny fixture).
+    oiio_add_tests (png-bomb ENABLEVAR ENABLE_PNG)
     oiio_add_tests (pnm
                     ENABLEVAR ENABLE_PNM
                     IMAGEDIR oiio-images)
diff --git a/src/dds.imageio/ddsinput.cpp b/src/dds.imageio/ddsinput.cpp
index 4bf4806438..355cddd3b2 100644
--- a/src/dds.imageio/ddsinput.cpp
+++ b/src/dds.imageio/ddsinput.cpp
@@ -944,6 +944,13 @@ DDSInput::seek_subimage(int subimage, int miplevel)
             return false;
     }
 
+    // Decompression-bomb guard: reject a tiny file that declares a huge
+    // decoded image before internal_readimg() commits to the m_buf allocation.
+    // For compressed formats the declared bytes are the decoded (RGBA/half)
+    // size; genuine BCn ratios are well under the default cap.
+    if (!check_compression_ratio(m_spec, ioproxy()->size()))
+        return false;
+
     m_subimage = subimage;
     m_miplevel = miplevel;
     return true;
diff --git a/src/dpx.imageio/dpxinput.cpp b/src/dpx.imageio/dpxinput.cpp
index 63934f6450..878552fad8 100644
--- a/src/dpx.imageio/dpxinput.cpp
+++ b/src/dpx.imageio/dpxinput.cpp
@@ -213,7 +213,8 @@ DPXInput::seek_subimage(int subimage, int miplevel)
     m_spec = ImageSpec(m_dpx.header.Width(), m_dpx.header.Height(),
                        m_dpx.header.ImageElementComponentCount(subimage),
                        typedesc);
-    if (!check_open(m_spec, { 0, 1 << 30, 0, 1 << 30, 0, 1 << 16, 0, 8 }))
+    if (!check_open(m_spec, { 0, 1 << 30, 0, 1 << 30, 0, 1 << 16, 0, 8 })
+        || !check_compression_ratio(m_spec, m_filesize))
         return false;
 
     // xOffset/yOffset are defined as unsigned 32-bit integers, but m_spec.x/y are signed
diff --git a/src/fits.imageio/fitsinput.cpp b/src/fits.imageio/fitsinput.cpp
index ec36509fa7..648c697996 100644
--- a/src/fits.imageio/fitsinput.cpp
+++ b/src/fits.imageio/fitsinput.cpp
@@ -191,6 +191,19 @@ FitsInput::set_spec_info()
         m_spec.set_format(TypeDesc::FLOAT);
     else if (m_bitpix == -64)
         m_spec.set_format(TypeDesc::DOUBLE);
+
+    // Validate dimensions and implied size for non-empty images. FITS permits
+    // an empty (0x0) primary HDU, which we pass through as metadata-only.
+    if (m_spec.width > 0 && m_spec.height > 0) {
+        if (m_spec.format == TypeDesc::UNKNOWN) {
+            errorfmt("Unsupported FITS BITPIX value {}", m_bitpix);
+            return false;
+        }
+        if (!check_open(m_spec, { 0, 1 << 20, 0, 1 << 20, 0, 1 << 16, 0, 4 }))
+            return false;
+        if (!check_compression_ratio(m_spec, Filesystem::file_size(m_filename)))
+            return false;
+    }
     return true;
 }
 
diff --git a/src/fuzz/populate_corpora.py b/src/fuzz/populate_corpora.py
index 4c85905a7c..8468b58a8e 100644
--- a/src/fuzz/populate_corpora.py
+++ b/src/fuzz/populate_corpora.py
@@ -56,6 +56,7 @@ def _find_images_root() -> Path:
         ("../bmpsuite",              ["bmp", "BMP"]),
     ],
     "cineon": [
+        ("testsuite/cineon/src",     ["cin"]),
         ("../oiio-images/cineon",    ["cin"]),
         ("../oiio-images",           ["cin"]),
     ],
@@ -68,25 +69,32 @@ def _find_images_root() -> Path:
         ("testsuite/dicom/src",      ["dcm"]),
     ],
     "dpx": [
+        ("testsuite/dpx/src",        ["dpx"]),
         ("../oiio-images/dpx",       ["dpx"]),
         ("../dpx-images-spi",        ["dpx"]),
     ],
     "openexr": [
+        ("testsuite/openexr-bomb/src", ["exr"]),
         ("../oiio-images",           ["exr"]),
         ("testsuite/oiio-images",    ["exr"]),
     ],
     "ffmpeg": [
         ("testsuite/ffmpeg/ref",     ["mkv", "mov", "mp4", "avi"]),
+        ("testsuite/ffmpeg/src",     ["mkv", "mov", "mp4", "avi"]),
     ],
     "fits": [
+        ("testsuite/fits/src",       ["fits", "fit"]),
         ("../fits-images/ftt4b",     ["fits", "fit"]),
         ("../fits-images/pg93",      ["fits", "fit"]),
     ],
     "gif": [
+        ("testsuite/gif/src",        ["gif"]),
         ("../oiio-images/gif",       ["gif"]),
     ],
     # hdr: synthetic seed committed; no further sources needed
-    "hdr": [],
+    "hdr": [
+        ("testsuite/hdr/src",        ["hdr", "rgbe"]),
+    ],
     "heif": [
         ("../oiio-images/heif",      ["heif", "heic", "avif"]),
         ("../heif-images",           ["heif", "heic", "avif"]),
@@ -96,22 +104,30 @@ def _find_images_root() -> Path:
         ("../oiio-images/ico",       ["ico"]),
     ],
     # iff: synthetic seed committed; no further sources needed
-    "iff": [],
+    "iff": [
+        ("testsuite/iff/src",        ["iff", "z"]),
+    ],
     "jpeg": [
+        ("testsuite/jpeg-corrupt/src", ["jpg", "jpeg"]),
         ("../oiio-images/jpeg",      ["jpg", "jpeg"]),
         ("testsuite/jpeg/src",       ["jpg", "jpeg"]),
         ("../oiio-images",           ["jpg", "jpeg"]),
     ],
     "jpeg2000": [
+        ("testsuite/htj2k/src",      ["j2c"]),
         ("../oiio-images/jpeg2000",  ["jp2", "j2k"]),
         ("../j2kp4files_v1_5/codestreams_profile0", ["j2k"]),
     ],
-    # jpegxl: synthetic seed committed; no further sources needed
-    "jpegxl": [],
+    "jpegxl": [
+        ("testsuite/jxl/src",        ["jxl"]),
+    ],
     "openvdb": [
         ("testsuite/openvdb/src",    ["vdb"]),
+        ("testsuite/openvdb-damaged/src", ["vdb"]),
     ],
     "png": [
+        ("testsuite/png-bomb/src",   ["png"]),
+        ("testsuite/png-damaged/src", ["png"]),
         ("../oiio-images/png",       ["png"]),
     ],
     "pnm": [
@@ -126,6 +142,7 @@ def _find_images_root() -> Path:
         ("testsuite/ptex/src",       ["ptx", "ptex"]),
     ],
     "raw": [
+        ("testsuite/raw/src",        ["dng"]),
         ("../oiio-images/raw",       ["cr2", "nef", "arw", "raf", "rw2", "orf",
                                       "CR2", "NEF", "ARW", "RAF", "RW2", "ORF"]),
     ],
@@ -133,8 +150,10 @@ def _find_images_root() -> Path:
         ("testsuite/rla/src",        ["rla"]),
         ("../oiio-images/rla",       ["rla"]),
     ],
-    # sgi: synthetic seed committed; no further sources needed
-    "sgi": [],
+    "sgi": [
+        ("testsuite/sgi/src",        ["sgi", "rgb", "rgba", "bw", "int", "inta"]),
+        ("../oiio-images",           ["sgi", "rgb"]),
+    ],
     "softimage": [
         ("testsuite/softimage/src",  ["pic"]),
         ("../oiio-images/softimage", ["pic"]),
@@ -149,10 +168,12 @@ def _find_images_root() -> Path:
         ("testsuite/tiff-suite/src", ["tif", "tiff"]),
     ],
     "webp": [
+        ("testsuite/webp/src",       ["webp"]),
         ("../oiio-images/webp",      ["webp"]),
     ],
     # zfile: use the reference output produced by the testsuite (a valid zfile)
     "zfile": [
+        ("testsuite/zfile/src",      ["zfile"]),
         ("testsuite/zfile/ref",      ["zfile"]),
     ],
 }
diff --git a/src/gif.imageio/gifinput.cpp b/src/gif.imageio/gifinput.cpp
index 4fa9c5e842..a13ffa45af 100644
--- a/src/gif.imageio/gifinput.cpp
+++ b/src/gif.imageio/gifinput.cpp
@@ -460,7 +460,8 @@ GIFInput::seek_subimage(int subimage, int miplevel)
     m_spec.full_width  = m_spec.width;
     m_spec.full_depth  = m_spec.depth;
 
-    if (!check_open(m_spec, { 0, 32768, 0, 32768, 0, 1, 0, 4 })) {
+    if (!check_open(m_spec, { 0, 32768, 0, 32768, 0, 1, 0, 4 })
+        || !check_compression_ratio(m_spec, ioproxy()->size())) {
         return false;
     }
 
diff --git a/src/hdr.imageio/hdrinput.cpp b/src/hdr.imageio/hdrinput.cpp
index d6ae224369..22a8d7e5a2 100644
--- a/src/hdr.imageio/hdrinput.cpp
+++ b/src/hdr.imageio/hdrinput.cpp
@@ -256,7 +256,8 @@ HdrInput::open(const std::string& name, ImageSpec& newspec)
     m_spec.full_width  = m_spec.width;
     m_spec.full_height = m_spec.height;
     // Validation of resolution
-    if (!check_open(m_spec, { 0, 65535, 0, 65535, 0, 1, 0, 4 })) {
+    if (!check_open(m_spec, { 0, 65535, 0, 65535, 0, 1, 0, 4 })
+        || !check_compression_ratio(m_spec, ioproxy()->size())) {
         close();
         return false;
     }
diff --git a/src/heif.imageio/heifinput.cpp b/src/heif.imageio/heifinput.cpp
index fa703b63bb..b135f4b8fe 100644
--- a/src/heif.imageio/heifinput.cpp
+++ b/src/heif.imageio/heifinput.cpp
@@ -299,6 +299,17 @@ HeifInput::seek_subimage(int subimage, int miplevel)
                                                      : heif_channel_interleaved;
     const int nchannels              = is_monochrome ? 1 : m_has_alpha ? 4 : 3;
 
+    // Validate the handle's declared dimensions against OIIO's limits BEFORE
+    // asking libheif to decode (and allocate) the full image. libheif has its
+    // own internal security limits, but this additionally enforces OIIO's
+    // limits:* policy and rejects degenerate (zero/negative) dimensions.
+    m_spec = ImageSpec(m_ihandle.get_width(), m_ihandle.get_height(), nchannels,
+                       (m_bitdepth > 8) ? TypeUInt16 : TypeUInt8);
+    if (!check_open(m_spec, { 0, 1 << 18, 0, 1 << 18, 0, 1, 0, 4 })) {
+        m_ctx.reset();
+        return false;
+    }
+
 #if 0
     try {
         m_himage = m_ihandle.decode_image(heif_colorspace_RGB, chroma);
diff --git a/src/ico.imageio/icoinput.cpp b/src/ico.imageio/icoinput.cpp
index f25740415d..946ceee911 100644
--- a/src/ico.imageio/icoinput.cpp
+++ b/src/ico.imageio/icoinput.cpp
@@ -243,7 +243,8 @@ ICOInput::seek_subimage(int subimage, int miplevel)
         bool ok = PNG_pvt::read_info(m_png, m_info, m_bpp, m_color_type,
                                      m_interlace_type, m_bg, m_spec, true);
         if (!ok || m_err
-            || !check_open(m_spec, { 0, 1 << 30, 0, 1 << 30, 0, 1, 0, 4 })) {
+            || !check_open(m_spec, { 0, 1 << 30, 0, 1 << 30, 0, 1, 0, 4 })
+            || !check_compression_ratio(m_spec, ioproxy()->size())) {
             return false;
         }
 
diff --git a/src/iff.imageio/iffinput.cpp b/src/iff.imageio/iffinput.cpp
index e965dfa298..602a4cf7b1 100644
--- a/src/iff.imageio/iffinput.cpp
+++ b/src/iff.imageio/iffinput.cpp
@@ -283,10 +283,9 @@ IffInput::open(const std::string& name, ImageSpec& spec)
     // we save this position - it will be helpful in read_native_tile
     m_tbmp_start = m_header.tbmp_start;
 
-    // Validity check resolutions. Width and height are a uint16, but this is
-    // an old format, we are guessing that there are no Maya IFF files that
-    // are > 64k pixels per side.
-    if (!check_open(m_spec, { 0, 1 << 16, 0, 1 << 16, 0, 1, 0, 5 }))
+    // Validity check resolutions and check for decompression bombs.
+    if (!check_open(m_spec, { 0, 1 << 16, 0, 1 << 16, 0, 1, 0, 5 })
+        || !check_compression_ratio(m_spec, ioproxy()->size()))
         return false;
 
     spec = m_spec;
diff --git a/src/jpeg.imageio/jpeginput.cpp b/src/jpeg.imageio/jpeginput.cpp
index cacd06d337..53f136f711 100644
--- a/src/jpeg.imageio/jpeginput.cpp
+++ b/src/jpeg.imageio/jpeginput.cpp
@@ -274,9 +274,16 @@ JpgInput::open(const std::string& name, ImageSpec& newspec)
     m_spec = ImageSpec(m_cinfo.output_width, m_cinfo.output_height, nchannels,
                        TypeDesc::UINT8);
 
+    // Validity check resolutions.
     if (!check_open(m_spec, { 0, 1 << 16, 0, 1 << 16, 0, 1, 0, 3 }))
         return false;
 
+    // check_open's size cap still admits dimensions that are absurd for a tiny
+    // file, so also bound the declared-vs-compressed ratio.
+    imagesize_t filesize = m_io ? m_io->size() : Filesystem::file_size(name);
+    if (!check_compression_ratio(m_spec, filesize))
+        return false;
+
     // Assume JPEG is in sRGB unless the Exif or XMP tags say otherwise.
     m_spec.set_colorspace("srgb_rec709_scene");
 
diff --git a/src/libOpenImageIO/imageinput.cpp b/src/libOpenImageIO/imageinput.cpp
index e400d6eff2..2e3c87dc36 100644
--- a/src/libOpenImageIO/imageinput.cpp
+++ b/src/libOpenImageIO/imageinput.cpp
@@ -1725,6 +1725,25 @@ ImageInput::check_open(const ImageSpec& spec, ROI range, uint64_t /*flags*/)
         return false;
     }
 
+    // Check for sensible tile sizes. A tile dimension of 0 means "not
+    // tiled", which is always fine; only reject negative sizes and tile
+    // dimensions that exceed the same per-format ceiling already applied
+    // to the image resolution above.
+    if (spec.tile_width < 0 || spec.tile_height < 0 || spec.tile_depth < 0) {
+        errorfmt(
+            "{} tile size may not be negative, but was {}x{}x{}. Possible corrupt input?",
+            format_name(), spec.tile_width, spec.tile_height, spec.tile_depth);
+        return false;
+    }
+    if (spec.tile_width > range.width() || spec.tile_height > range.height()
+        || spec.tile_depth > range.depth()) {
+        errorfmt(
+            "{} tile size may not exceed {}x{}x{}, but was {}x{}x{}. Possible corrupt input?",
+            format_name(), range.width(), range.height(), range.depth(),
+            spec.tile_width, spec.tile_height, spec.tile_depth);
+        return false;
+    }
+
     // Check for invalid full_* values for sensibility
     if (spec.full_width == 0 && spec.full_height == 0 && spec.full_depth == 0
         && supports("noimage")) {
diff --git a/src/null.imageio/nullimageio.cpp b/src/null.imageio/nullimageio.cpp
index 89afc9c0c6..917c1684e4 100644
--- a/src/null.imageio/nullimageio.cpp
+++ b/src/null.imageio/nullimageio.cpp
@@ -319,6 +319,14 @@ NullInput::open(const std::string& name, ImageSpec& newspec,
         }
     }
 
+    // The query arguments above are parsed input, even though no file is
+    // ever read. Without this, "foo.null?CHANNELS=-1" sign-extended its way
+    // into a std::length_error that nothing catches, "RES=-4x-4" handed the
+    // caller a negative-sized spec, and a large enough CHANNELS hung building
+    // channel names. check_open() also rejects a negative or oversized TILE.
+    if (!check_open(m_topspec, ROI(0, 1 << 20, 0, 1 << 20, 0, 1 << 20, 0, 1024)))
+        return false;
+
     m_value.resize(m_topspec.pixel_bytes());  // default fills with 0's
     if (fvalue.size()) {
         // Convert float to the native type
diff --git a/src/openexr.imageio/exrinput.cpp b/src/openexr.imageio/exrinput.cpp
index 31dcb516a2..c2015b85f6 100644
--- a/src/openexr.imageio/exrinput.cpp
+++ b/src/openexr.imageio/exrinput.cpp
@@ -1137,6 +1137,13 @@ OpenEXRInput::seek_subimage(int subimage, int miplevel)
     if (!check_open(m_spec, { 0, 1 << 30, 0, 1 << 30, 0, 1, 0, 1 << 12 }))
         return false;
 
+    // check_open's size cap still admits a dataWindow that is absurd for a tiny
+    // compressed file, so also bound the declared-vs-compressed ratio.
+    imagesize_t filesize = m_io ? m_io->size()
+                                : Filesystem::file_size(m_filename);
+    if (!check_compression_ratio(m_spec, filesize))
+        return false;
+
     if (miplevel == 0 && part.levelmode == Imf::ONE_LEVEL) {
         return true;
     }
diff --git a/src/openexr.imageio/exrinput_c.cpp b/src/openexr.imageio/exrinput_c.cpp
index 8933d3e77e..f4f7b6a8cc 100644
--- a/src/openexr.imageio/exrinput_c.cpp
+++ b/src/openexr.imageio/exrinput_c.cpp
@@ -1121,6 +1121,13 @@ OpenEXRCoreInput::seek_subimage(int subimage, int miplevel)
     if (!check_open(m_spec, { 0, 1 << 30, 0, 1 << 30, 0, 1, 0, 1 << 12 }))
         return false;
 
+    // check_open's size cap still admits a dataWindow that is absurd for a tiny
+    // compressed file, so also bound the declared-vs-compressed ratio.
+    imagesize_t filesize = m_userdata.m_io ? m_userdata.m_io->size()
+                                           : Filesystem::file_size(m_filename);
+    if (!check_compression_ratio(m_spec, filesize))
+        return false;
+
     if (miplevel == 0 && part.levelmode == EXR_TILE_ONE_LEVEL) {
         return true;
     }
diff --git a/src/png.imageio/pnginput.cpp b/src/png.imageio/pnginput.cpp
index 02841868b8..55afc89ee8 100644
--- a/src/png.imageio/pnginput.cpp
+++ b/src/png.imageio/pnginput.cpp
@@ -183,6 +183,15 @@ PNGInput::open(const std::string& name, ImageSpec& newspec)
         return false;
     }
 
+    // check_open's size cap still admits dimensions that are absurd for a tiny
+    // compressed file, so also bound the declared-vs-compressed ratio.
+    imagesize_t filesize = ioproxy() ? ioproxy()->size()
+                                     : Filesystem::file_size(m_filename);
+    if (!check_compression_ratio(m_spec, filesize)) {
+        close();
+        return false;
+    }
+
     string_view colorspace = m_spec.get_string_attribute("oiio:ColorSpace",
                                                          "srgb_rec709_scene");
     const ColorConfig& colorconfig(ColorConfig::default_colorconfig());
diff --git a/src/pnm.imageio/pnminput.cpp b/src/pnm.imageio/pnminput.cpp
index 959d3a749e..6d1cb90bf5 100644
--- a/src/pnm.imageio/pnminput.cpp
+++ b/src/pnm.imageio/pnminput.cpp
@@ -515,6 +515,13 @@ PNMInput::open(const std::string& name, ImageSpec& newspec)
     if (!check_open(m_spec))  // check for apparently invalid values
         return false;
 
+    // Reject a tiny file that declares a huge image before the caller
+    // allocates the full (declared) pixel buffer. Binary PNM data must be
+    // present in the file and ASCII values cost >=2 bytes each, so a
+    // legitimate file never has an extreme ratio.
+    if (!check_compression_ratio(m_spec, m_io->size()))
+        return false;
+
     m_remaining    = append_remainder_to_buffer(m_file_contents, m_io,
                                                 m_remaining);
     m_after_header = m_remaining;
diff --git a/src/rla.imageio/rlainput.cpp b/src/rla.imageio/rlainput.cpp
index 68ef176f9f..9f73542f34 100644
--- a/src/rla.imageio/rlainput.cpp
+++ b/src/rla.imageio/rlainput.cpp
@@ -331,6 +331,11 @@ RLAInput::seek_subimage(int subimage, int miplevel)
                               3 + 3 + 256 }))
         return false;
 
+    // Check for uncompressed size that is wildly out of proportion to
+    // file size.
+    if (!check_compression_ratio(m_spec, ioproxy()->size()))
+        return false;
+
     // set channel formats and stride
     int z_channel = -1;
     m_stride      = 0;
diff --git a/src/sgi.imageio/sgiinput.cpp b/src/sgi.imageio/sgiinput.cpp
index 9b6efa6843..2c1364628e 100644
--- a/src/sgi.imageio/sgiinput.cpp
+++ b/src/sgi.imageio/sgiinput.cpp
@@ -159,7 +159,8 @@ SgiInput::open(const std::string& name, ImageSpec& spec)
                        m_sgi_header.bpc == 1 ? TypeDesc::UINT8
                                              : TypeDesc::UINT16);
 
-    if (!check_open(m_spec, { 0, 65535, 0, 65535, 0, 1, 0, 4 })) {
+    if (!check_open(m_spec, { 0, 65535, 0, 65535, 0, 1, 0, 4 })
+        || !check_compression_ratio(m_spec, ioproxy()->size())) {
         close();
         return false;
     }
diff --git a/src/softimage.imageio/softimageinput.cpp b/src/softimage.imageio/softimageinput.cpp
index 69c9956b0e..47b0336285 100644
--- a/src/softimage.imageio/softimageinput.cpp
+++ b/src/softimage.imageio/softimageinput.cpp
@@ -212,7 +212,8 @@ SoftimageInput::open(const std::string& name, ImageSpec& spec)
     m_spec = ImageSpec(m_pic_header.width, m_pic_header.height, nchannels,
                        widest);
 
-    if (!check_open(m_spec, { 0, 65535, 0, 65535, 0, 1, 0, 4 })) {
+    if (!check_open(m_spec, { 0, 65535, 0, 65535, 0, 1, 0, 4 })
+        || !check_compression_ratio(m_spec, Filesystem::file_size(m_filename))) {
         close();
         return false;
     }
diff --git a/src/webp.imageio/webpinput.cpp b/src/webp.imageio/webpinput.cpp
index ae2b36c57d..d30b568f68 100644
--- a/src/webp.imageio/webpinput.cpp
+++ b/src/webp.imageio/webpinput.cpp
@@ -241,6 +241,13 @@ WebpInput::open(const std::string& name, ImageSpec& spec,
         }
     }
 
+    // Validate the declared canvas extents and the implied uncompressed size
+    // BEFORE allocating the decoded-image buffer, so a malformed header cannot
+    // drive a large allocation.
+    if (!check_open(m_spec, { 0, (1 << 14) - 1, 0, (1 << 14) - 1, 0, 1, 0, 4 })
+        || !check_compression_ratio(m_spec, m_image_size))
+        return false;
+
     // Make space for the decoded image
     m_decoded_image.reset(new uint8_t[m_spec.image_bytes()]);
 
@@ -250,9 +257,6 @@ WebpInput::open(const std::string& name, ImageSpec& spec,
             m_spec.attribute("oiio:UnassociatedAlpha", 1);
     }
 
-    if (!check_open(m_spec, { 0, (1 << 14) - 1, 0, (1 << 14) - 1, 0, 1, 0, 4 }))
-        return false;
-
     seek_subimage(0, 0);
     spec = m_spec;
     return true;
diff --git a/src/zfile.imageio/zfile.cpp b/src/zfile.imageio/zfile.cpp
index d2e326aa4a..56273a9197 100644
--- a/src/zfile.imageio/zfile.cpp
+++ b/src/zfile.imageio/zfile.cpp
@@ -189,6 +189,12 @@ ZfileInput::open(const std::string& name, ImageSpec& newspec)
     }
 
     m_spec = ImageSpec(header.width, header.height, 1, TypeDesc::FLOAT);
+    // The reader had no open-time validation: header.width/height are signed
+    // 16-bit and could be negative or zero, and a tiny file could declare a
+    // huge (gzip-bomb) image. Reject both before the caller allocates.
+    if (!check_open(m_spec, { 0, 32767, 0, 32767, 0, 1, 0, 1 })
+        || !check_compression_ratio(m_spec, Filesystem::file_size(m_filename)))
+        return false;
     if (m_spec.channelnames.size() == 0)
         m_spec.channelnames.resize(1);
     m_spec.channelnames[0] = std::string("z");
diff --git a/testsuite/cineon/ref/out.txt b/testsuite/cineon/ref/out.txt
index 07f06a1928..e1a2ef796f 100644
--- a/testsuite/cineon/ref/out.txt
+++ b/testsuite/cineon/ref/out.txt
@@ -39,3 +39,6 @@ Full command line was:
 oiiotool ERROR: read : "src/broken_bitdepth2.cin": Invalid bitdepth in channel 0: 26 bits
 Full command line was:
 > oiiotool --info --hash src/broken_bitdepth2.cin
+oiiotool ERROR: read : "src/bomb-46341.cin": cineon header claims a 12288 MB image from a 2048 byte file; probably a corrupt or malicious header
+Full command line was:
+> oiiotool --info --hash src/bomb-46341.cin
diff --git a/testsuite/cineon/run.py b/testsuite/cineon/run.py
index 9e01f91ed5..a8bc24b3d7 100755
--- a/testsuite/cineon/run.py
+++ b/testsuite/cineon/run.py
@@ -17,5 +17,9 @@
 # Regression test for a per-channel bit depth libcineon doesn't recognize
 # (used to assert/abort inside CineonHeader.cpp instead of erroring out).
 command += info_command ("src/broken_bitdepth2.cin", verbose=False, failureok=True)
+# Regression test: a 2 KB Cineon header declaring a ~12 GB image
+# (46341x46341x3) -- a decompression bomb the compression-ratio guard must
+# reject before any large allocation.
+command += info_command ("src/bomb-46341.cin", verbose=False, failureok=True)
 
 outputs = [ "out.txt" ]
diff --git a/testsuite/cineon/src/bomb-46341.cin b/testsuite/cineon/src/bomb-46341.cin
new file mode 100644
index 0000000000..c7a5abe2dd
Binary files /dev/null and b/testsuite/cineon/src/bomb-46341.cin differ
diff --git a/testsuite/dpx/ref/out.txt b/testsuite/dpx/ref/out.txt
index d4c13b5d2e..df2109bf80 100644
--- a/testsuite/dpx/ref/out.txt
+++ b/testsuite/dpx/ref/out.txt
@@ -219,3 +219,6 @@ src/crash-1chan-10bit-filled-methodA.dpx :   80 x   60, 3 channel, uint10 dpx
     oiio:BitsPerSample: 10
     oiio:subimages: 2
     smpte:TimeCode: 00:00:00:00
+oiiotool ERROR: read : "src/bomb-46341.dpx": dpx header claims a 12288 MB image from a 21248 byte file; probably a corrupt or malicious header
+Full command line was:
+> oiiotool --info -v -a --no-metamatch DateTime|Software|OriginatingProgram|ImageHistory --hash src/bomb-46341.dpx
diff --git a/testsuite/dpx/run.py b/testsuite/dpx/run.py
index 1acaee89e7..1f6c46a2db 100755
--- a/testsuite/dpx/run.py
+++ b/testsuite/dpx/run.py
@@ -45,3 +45,8 @@
 # remained for the last (partial) group in the scanline, writing/reading
 # one uint16 past the end of the caller's scanline buffer.
 command += info_command("src/crash-1chan-10bit-filled-methodA.dpx", safematch=True)
+
+# Regression test: a 21 KB DPX whose header declares a ~12 GB image
+# (46341x46341x3) -- a decompression bomb the compression-ratio guard must
+# reject before any large allocation.
+command += info_command("src/bomb-46341.dpx", safematch=True, failureok=True)
diff --git a/testsuite/dpx/src/bomb-46341.dpx b/testsuite/dpx/src/bomb-46341.dpx
new file mode 100644
index 0000000000..da9413b8f5
Binary files /dev/null and b/testsuite/dpx/src/bomb-46341.dpx differ
diff --git a/testsuite/gif/ref/out.txt b/testsuite/gif/ref/out.txt
index 30ce27631e..aebb422f76 100644
--- a/testsuite/gif/ref/out.txt
+++ b/testsuite/gif/ref/out.txt
@@ -109,6 +109,6 @@ tahoe-tiny.gif       :  128 x   96, 4 channel, uint8 gif
 oiiotool ERROR: read : "src/crash_4163.gif": Wrong record type detected
 Full command line was:
 > oiiotool -nostderr -oiioattrib try_all_readers 0 src/crash_4163.gif -o test.exr
-oiiotool ERROR: read : "src/gif_idx_overflow_32768x16385_top16384_1x1.gif": GIF image canvas is too large
+oiiotool ERROR: read : "src/gif_idx_overflow_32768x16385_top16384_1x1.gif": gif header claims a 2048 MB image from a 35 byte file; probably a corrupt or malicious header
 Full command line was:
 > oiiotool --info -oiioattrib try_all_readers 0 src/gif_idx_overflow_32768x16385_top16384_1x1.gif
diff --git a/testsuite/hdr/ref/out.txt b/testsuite/hdr/ref/out.txt
index e4fbc081ee..f8d8c37169 100644
--- a/testsuite/hdr/ref/out.txt
+++ b/testsuite/hdr/ref/out.txt
@@ -25,3 +25,6 @@ MtTamWest.hdr        : 1214 x  732, 3 channel, float hdr
 oiiotool ERROR: read : "src/crash-res.hdr": hdr image resolution may not exceed 65535x65535, but the file appears to be 8888888x4. Possible corrupt input?
 Full command line was:
 > oiiotool -nostderr -oiioattrib try_all_readers 0 src/crash-res.hdr -o test.exr
+oiiotool ERROR: read : "src/bomb-40000.hdr": hdr header claims a 18310 MB image from a 53 byte file; probably a corrupt or malicious header
+Full command line was:
+> oiiotool -nostderr -oiioattrib try_all_readers 0 -info src/bomb-40000.hdr
diff --git a/testsuite/hdr/run.py b/testsuite/hdr/run.py
index 3c21d3d05b..14102337a3 100755
--- a/testsuite/hdr/run.py
+++ b/testsuite/hdr/run.py
@@ -14,3 +14,8 @@
 
 # Regression test: invalid resolution
 command += oiiotool ("-nostderr -oiioattrib try_all_readers 0 src/crash-res.hdr -o test.exr", failureok = True)
+
+# Regression test: a 53-byte header declaring a ~18 GB image (40000x40000).
+# The compression-ratio guard must reject it before the caller allocates the
+# full pixel buffer.
+command += oiiotool ("-nostderr -oiioattrib try_all_readers 0 -info src/bomb-40000.hdr", failureok=True)
diff --git a/testsuite/hdr/src/bomb-40000.hdr b/testsuite/hdr/src/bomb-40000.hdr
new file mode 100644
index 0000000000..e8d2f7e946
--- /dev/null
+++ b/testsuite/hdr/src/bomb-40000.hdr
@@ -0,0 +1,4 @@
+#?RADIANCE
+FORMAT=32-bit_rle_rgbe
+
+-Y 40000 +X 40000
diff --git a/testsuite/ico/ref/out.txt b/testsuite/ico/ref/out.txt
index e3fd37e584..e7da25958b 100644
--- a/testsuite/ico/ref/out.txt
+++ b/testsuite/ico/ref/out.txt
@@ -50,3 +50,4 @@ iconvert ERROR copying "src/crash-002c.ico" to "out.tif" :
 	Read error: hit end of file in ico reader
 iconvert ERROR copying "src/bad-palette.ico" to "out.tif" :
 	Possible corruption: index exceeds palette size
+iconvert ERROR: ico header claims a 6143 MB image from a 375 byte file; probably a corrupt or malicious header
diff --git a/testsuite/ico/run.py b/testsuite/ico/run.py
index d4f5cf8ba7..93487d6ea8 100755
--- a/testsuite/ico/run.py
+++ b/testsuite/ico/run.py
@@ -12,4 +12,7 @@
 command += iconvert ("src/crash-002c.ico out.tif")
 command += iconvert ("src/bad-not-8x-wide.ico out.tif")
 command += iconvert ("src/bad-palette.ico out.tif")
+# ICO embedding a PNG whose IHDR declares a ~6 GB image (46340x46340). The
+# compression-ratio guard must reject it before the PNG buffer is allocated.
+command += iconvert ("src/bomb-png-46340.ico out.tif")
 
diff --git a/testsuite/ico/src/bomb-png-46340.ico b/testsuite/ico/src/bomb-png-46340.ico
new file mode 100644
index 0000000000..11914a3a49
Binary files /dev/null and b/testsuite/ico/src/bomb-png-46340.ico differ
diff --git a/testsuite/iff/ref/out.txt b/testsuite/iff/ref/out.txt
index 25960a1142..51e226716a 100644
--- a/testsuite/iff/ref/out.txt
+++ b/testsuite/iff/ref/out.txt
@@ -19,3 +19,6 @@ oiiotool ERROR: read : "src/zbuffer_only.iff": IFF error ZBUFFER-only (Z-depth)
 IFF error could not read header
 Full command line was:
 > oiiotool --info -v -a --hash src/zbuffer_only.iff
+oiiotool ERROR: read : "src/bomb-46341.iff": iff header claims a 8192 MB image from a 336 byte file; probably a corrupt or malicious header
+Full command line was:
+> oiiotool --info -v -a --hash src/bomb-46341.iff
diff --git a/testsuite/iff/run.py b/testsuite/iff/run.py
index 9a0c940b46..395740718c 100755
--- a/testsuite/iff/run.py
+++ b/testsuite/iff/run.py
@@ -20,3 +20,7 @@
 # ImageSpec while the internal pixel size stayed 32-bit, causing
 # read_native_tile to write past the caller's tile buffer. Must be rejected.
 command += info_command("src/zbuffer_only.iff", hash=True, failureok=True)
+# Regression test: a 336-byte IFF whose TBHD declares a ~8 GB image
+# (46341x46341x4) -- a decompression bomb the compression-ratio guard must
+# reject before any large allocation.
+command += info_command("src/bomb-46341.iff", hash=True, failureok=True)
diff --git a/testsuite/iff/src/bomb-46341.iff b/testsuite/iff/src/bomb-46341.iff
new file mode 100644
index 0000000000..c3fc83b8df
Binary files /dev/null and b/testsuite/iff/src/bomb-46341.iff differ
diff --git a/testsuite/openexr-bomb/ref/out-exr22.txt b/testsuite/openexr-bomb/ref/out-exr22.txt
new file mode 100644
index 0000000000..f9eea90c8e
--- /dev/null
+++ b/testsuite/openexr-bomb/ref/out-exr22.txt
@@ -0,0 +1,6 @@
+oiiotool ERROR: read : OpenEXR exception: Cannot read image file "src/bomb.exr". Unexpected end of file.
+Full command line was:
+> oiiotool -oiioattrib openexr:core 0 --info -v src/bomb.exr
+oiiotool ERROR: read : "src/bomb.exr": openexr header claims a 12287 MB image from a 464 byte file; probably a corrupt or malicious header
+Full command line was:
+> oiiotool -oiioattrib openexr:core 1 --info -v src/bomb.exr
diff --git a/testsuite/openexr-bomb/ref/out.txt b/testsuite/openexr-bomb/ref/out.txt
new file mode 100644
index 0000000000..df5f642624
--- /dev/null
+++ b/testsuite/openexr-bomb/ref/out.txt
@@ -0,0 +1,6 @@
+oiiotool ERROR: read : "src/bomb.exr": openexr header claims a 12287 MB image from a 464 byte file; probably a corrupt or malicious header
+Full command line was:
+> oiiotool -oiioattrib openexr:core 0 --info -v src/bomb.exr
+oiiotool ERROR: read : "src/bomb.exr": openexr header claims a 12287 MB image from a 464 byte file; probably a corrupt or malicious header
+Full command line was:
+> oiiotool -oiioattrib openexr:core 1 --info -v src/bomb.exr
diff --git a/testsuite/openexr-bomb/run.py b/testsuite/openexr-bomb/run.py
new file mode 100644
index 0000000000..aa2de94ca6
--- /dev/null
+++ b/testsuite/openexr-bomb/run.py
@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+
+# Copyright Contributors to the OpenImageIO project.
+# SPDX-License-Identifier: Apache-2.0
+# https://github.com/AcademySoftwareFoundation/OpenImageIO
+
+
+failureok = True
+redirect = ' >> out.txt 2>&1 '
+
+# src/bomb.exr is a tiny (464-byte) EXR whose dataWindow declares a ~12 GB
+# image: a decompression bomb. Both the C++ reader (openexr:core=0) and the
+# C-API core reader (openexr:core=1) must reject it with a bounded error
+# instead of attempting the enormous allocation.
+command += oiiotool("-oiioattrib openexr:core 0 --info -v src/bomb.exr",
+                    failureok=True)
+command += oiiotool("-oiioattrib openexr:core 1 --info -v src/bomb.exr",
+                    failureok=True)
diff --git a/testsuite/openexr-bomb/src/bomb.exr b/testsuite/openexr-bomb/src/bomb.exr
new file mode 100644
index 0000000000..a6d501ed93
Binary files /dev/null and b/testsuite/openexr-bomb/src/bomb.exr differ
diff --git a/testsuite/png-bomb/ref/out.txt b/testsuite/png-bomb/ref/out.txt
new file mode 100644
index 0000000000..a56cf0f4e0
--- /dev/null
+++ b/testsuite/png-bomb/ref/out.txt
@@ -0,0 +1,3 @@
+oiiotool ERROR: read : "src/bomb.png": png header claims a 6143 MB image from a 353 byte file; probably a corrupt or malicious header
+Full command line was:
+> oiiotool --info -v src/bomb.png
diff --git a/testsuite/png-bomb/run.py b/testsuite/png-bomb/run.py
new file mode 100644
index 0000000000..368d36bb37
--- /dev/null
+++ b/testsuite/png-bomb/run.py
@@ -0,0 +1,14 @@
+#!/usr/bin/env python
+
+# Copyright Contributors to the OpenImageIO project.
+# SPDX-License-Identifier: Apache-2.0
+# https://github.com/AcademySoftwareFoundation/OpenImageIO
+
+
+failureok = True
+redirect = ' >> out.txt 2>&1 '
+
+# src/bomb.png is a tiny (353-byte) PNG whose IHDR declares a ~6 GB image
+# (46340x46340x3): a decompression bomb. The reader must reject it with a
+# bounded error instead of attempting the enormous allocation.
+command += oiiotool("--info -v src/bomb.png", failureok=True)
diff --git a/testsuite/png-bomb/src/bomb.png b/testsuite/png-bomb/src/bomb.png
new file mode 100644
index 0000000000..50b5c8321d
Binary files /dev/null and b/testsuite/png-bomb/src/bomb.png differ
diff --git a/testsuite/pnm/ref/out.txt b/testsuite/pnm/ref/out.txt
index c1d480004f..3c2807f91f 100644
--- a/testsuite/pnm/ref/out.txt
+++ b/testsuite/pnm/ref/out.txt
@@ -83,3 +83,6 @@ Full command line was:
 oiiotool ERROR: read : "src/bad-4553.pgm": pnm image resolution may not exceed 65535x65535, but the file appears to be 2147483647x255. Possible corrupt input?
 Full command line was:
 > oiiotool --info -v -a --hash --oiioattrib try_all_readers 0 --printstats src/bad-4553.pgm
+oiiotool ERROR: read : "src/bomb-65000.pgm": pnm header claims a 4029 MB image from a 19 byte file; probably a corrupt or malicious header
+Full command line was:
+> oiiotool --info -v -a --no-metamatch DateTime|Software|OriginatingProgram|ImageHistory --hash src/bomb-65000.pgm
diff --git a/testsuite/pnm/run.py b/testsuite/pnm/run.py
index be6a094e82..7729debcba 100755
--- a/testsuite/pnm/run.py
+++ b/testsuite/pnm/run.py
@@ -23,3 +23,8 @@
 files = [ "src/bad-4552.pgm", "src/bad-4553.pgm" ]
 for f in files:
     command += info_command (f, extraargs="--oiioattrib try_all_readers 0 --printstats", failureok=True)
+
+# Decompression bomb: a 19-byte header declaring a ~4 GB image (65000x65000).
+# The compression-ratio guard must reject it before the caller allocates the
+# full pixel buffer.
+command += info_command ("src/bomb-65000.pgm", failureok=True, safematch=True)
diff --git a/testsuite/pnm/src/.gitattributes b/testsuite/pnm/src/.gitattributes
new file mode 100644
index 0000000000..72c3181b54
--- /dev/null
+++ b/testsuite/pnm/src/.gitattributes
@@ -0,0 +1 @@
+bomb-65000.pgm binary
diff --git a/testsuite/pnm/src/bomb-65000.pgm b/testsuite/pnm/src/bomb-65000.pgm
new file mode 100644
index 0000000000..5f63882f7e
--- /dev/null
+++ b/testsuite/pnm/src/bomb-65000.pgm
@@ -0,0 +1,3 @@
+P5
+65000 65000
+255
diff --git a/testsuite/sgi/ref/out.txt b/testsuite/sgi/ref/out.txt
index 63f1b50ff1..ca8c0019e6 100644
--- a/testsuite/sgi/ref/out.txt
+++ b/testsuite/sgi/ref/out.txt
@@ -49,3 +49,4 @@ src/broken_rle16_len1.sgi :    1 x    1, 1 channel, uint16 sgi
     channel list: Y
     compression: "rle"
 iinfo ERROR: "src/broken_rle16_len1.sgi" : Corrupt RLE data
+iinfo ERROR: "src/bomb-65535.sgi" : sgi header claims a 16383 MB image from a 512 byte file; probably a corrupt or malicious header
diff --git a/testsuite/sgi/run.py b/testsuite/sgi/run.py
index c15f74cdde..0cc96db5ee 100755
--- a/testsuite/sgi/run.py
+++ b/testsuite/sgi/run.py
@@ -28,3 +28,8 @@
 # broken_rle16_len1.sgi tests a 16 bit RLE file that has an odd byte count.
 command += info_command ("--stats src/broken_rle16_len1.sgi",
                          info_program="iinfo", failureok=True)
+# bomb-65535.sgi declares a ~16 GB image (65535x65535x4) from a 512-byte
+# header: a decompression bomb the compression-ratio guard must reject before
+# any large allocation.
+command += info_command ("--stats src/bomb-65535.sgi",
+                         info_program="iinfo", failureok=True)
diff --git a/testsuite/sgi/src/bomb-65535.sgi b/testsuite/sgi/src/bomb-65535.sgi
new file mode 100644
index 0000000000..1442f8ded2
Binary files /dev/null and b/testsuite/sgi/src/bomb-65535.sgi differ
diff --git a/testsuite/softimage/ref/out.txt b/testsuite/softimage/ref/out.txt
index 471e196acf..255fa1078d 100644
--- a/testsuite/softimage/ref/out.txt
+++ b/testsuite/softimage/ref/out.txt
@@ -44,6 +44,7 @@ src/broken01.pic :   16 x    4, 1 channel, uint8 softimage
     Stats FiniteCount: 64 
     Constant: No
     Monochrome: Yes
+iinfo ERROR: "src/bomb-40000.pic" : softimage header claims a 6103 MB image from a 118 byte file; probably a corrupt or malicious header
 src/mixed-bitdepth.pic :    2 x    1, 2 channel, uint16 softimage
     SHA-1: 52D6B72AAD7084E2ECF1550D500A66C42F408ED1
     channel list: R, G
diff --git a/testsuite/softimage/run.py b/testsuite/softimage/run.py
index 8c80afe8d6..a31841ff4a 100755
--- a/testsuite/softimage/run.py
+++ b/testsuite/softimage/run.py
@@ -13,6 +13,10 @@
 # Regression testing of error handling and corrupt files
 command += info_command ("--stats src/broken01.pic",
                          info_program="iinfo", failureok=True)
+# A 118-byte header declaring a ~6 GB image (40000x40000): the
+# compression-ratio guard must reject it before the caller allocates.
+command += info_command ("--stats src/bomb-40000.pic",
+                         info_program="iinfo", failureok=True)
 # A file whose channel packets use different bit depths (here a 16-bit R
 # packet and an 8-bit G packet): narrower channels get promoted to the
 # widest depth present. This used to overrun the scanline buffer because a
diff --git a/testsuite/softimage/src/bomb-40000.pic b/testsuite/softimage/src/bomb-40000.pic
new file mode 100644
index 0000000000..d8eb5e2823
Binary files /dev/null and b/testsuite/softimage/src/bomb-40000.pic differ
diff --git a/testsuite/targa/ref/out.txt b/testsuite/targa/ref/out.txt
index d7b8d03467..d1dedde899 100644
--- a/testsuite/targa/ref/out.txt
+++ b/testsuite/targa/ref/out.txt
@@ -209,6 +209,9 @@ Full command line was:
 oiiotool ERROR: read : "src/crash-20250423.tga": Corrupt palette index
 Full command line was:
 > oiiotool --oiioattrib try_all_readers 0 src/crash-20250423.tga -o out.null
+oiiotool ERROR: read : "src/crash-bomb-65535.tga": TGA header claims image size 12884508675 bytes, implausible for 0 bytes of remaining file data
+Full command line was:
+> oiiotool --oiioattrib try_all_readers 0 src/crash-bomb-65535.tga -o out.null
 Reading src/1x1.tga
 src/1x1.tga          :    1 x    1, 3 channel, uint2 targa
     SHA-1: DB9237F28F9622F7B7E73B783A8822B63BDB3708
diff --git a/testsuite/targa/run.py b/testsuite/targa/run.py
index ca4219cbc8..13f0b6f92f 100755
--- a/testsuite/targa/run.py
+++ b/testsuite/targa/run.py
@@ -28,6 +28,8 @@
                     "--oiioattrib try_all_readers 0 "
                     "src/crash3952.tga -o crash3952.exr", failureok = True)
 command += oiiotool("--oiioattrib try_all_readers 0 src/crash-20250423.tga -o out.null", failureok=True);
+# Tiny file declaring a huge image (decompression bomb) is rejected
+command += oiiotool("--oiioattrib try_all_readers 0 src/crash-bomb-65535.tga -o out.null", failureok=True);
 
 # Test odds and ends, unusual files
 command += rw_command("src", "1x1.tga")
diff --git a/testsuite/targa/src/crash-bomb-65535.tga b/testsuite/targa/src/crash-bomb-65535.tga
new file mode 100644
index 0000000000..09ba4a62f1
Binary files /dev/null and b/testsuite/targa/src/crash-bomb-65535.tga differ
diff --git a/testsuite/webp/ref/out-webp1.1.txt b/testsuite/webp/ref/out-webp1.1.txt
index edbdaa0cf1..76ec534165 100644
--- a/testsuite/webp/ref/out-webp1.1.txt
+++ b/testsuite/webp/ref/out-webp1.1.txt
@@ -29,3 +29,6 @@ short-exif-len4.webp-ok
 short-exif-len5.webp-ok
 short-exif-len6.webp-ok
 short-exif-len13.webp-ok
+oiiotool ERROR: read : "src/bomb-16383.webp": Couldn't decode
+Full command line was:
+> oiiotool --info -v -a --no-metamatch DateTime|Software|OriginatingProgram|ImageHistory --hash src/bomb-16383.webp
diff --git a/testsuite/webp/run.py b/testsuite/webp/run.py
index 091accdf1e..dbd1108e20 100755
--- a/testsuite/webp/run.py
+++ b/testsuite/webp/run.py
@@ -4,6 +4,8 @@
 # SPDX-License-Identifier: Apache-2.0
 # https://github.com/AcademySoftwareFoundation/OpenImageIO
 
+redirect = ' >> out.txt 2>&1 '
+
 files = [ "1.webp", "2.webp", "3.webp", "4.webp" ]
 for f in files:
     command += info_command (OIIO_TESTSUITE_IMAGEDIR + "/" + f)
@@ -27,3 +29,9 @@
 ]
 for f in short_exif_files:
     command += iconvert(f + " out.null", successmessage=f + "-ok")
+
+# Regression test: a 76-byte WebP whose VP8X header declares a 16383x16383
+# canvas inconsistent with its tiny frame. Must be rejected cleanly (libwebp's
+# demux catches the mismatch; the open-time check_open/compression-ratio guard
+# now runs before the decoded-image allocation regardless).
+command += info_command ("src/bomb-16383.webp", failureok=True, safematch=True)
diff --git a/testsuite/webp/src/bomb-16383.webp b/testsuite/webp/src/bomb-16383.webp
new file mode 100644
index 0000000000..e193a0f613
Binary files /dev/null and b/testsuite/webp/src/bomb-16383.webp differ