profullstack · CSTRSK · Aug 9, 2026
diff --git a/docs/VULNERABILITY_CATALOG.md b/docs/VULNERABILITY_CATALOG.md
@@ -7,12 +7,12 @@ from each file's header comment, so this page cannot drift from the source.
 
 ## Totals
 
-- **Test cases:** 62
-- **Expected detections:** 62
-- **`VULNERABLE:` markers:** 123 (individual lines a scanner should flag)
-- **`SAFE:` markers:** 73 (lines a scanner must not flag — the false-positive control group)
+- **Test cases:** 63
+- **Expected detections:** 63
+- **`VULNERABLE:` markers:** 124 (individual lines a scanner should flag)
+- **`SAFE:` markers:** 74 (lines a scanner must not flag — the false-positive control group)
 - **Languages:** 8 — dotenv, go, java, javascript, json, python, ruby, text
-- **CWE categories:** 46 — CWE-20, CWE-22, CWE-78, CWE-79, CWE-89, CWE-90, CWE-95, CWE-113, CWE-117, CWE-190, CWE-201, CWE-209, CWE-256, CWE-295, CWE-321, CWE-327, CWE-330, CWE-338, CWE-346, CWE-347, CWE-352, CWE-362, CWE-377, CWE-384, CWE-489, CWE-502, CWE-506, CWE-532, CWE-601, CWE-611, CWE-614, CWE-639, CWE-643, CWE-681, CWE-759, CWE-798, CWE-862, CWE-915, CWE-918, CWE-942, CWE-943, CWE-1236, CWE-1321, CWE-1333, CWE-1336, CWE-1357
+- **CWE categories:** 47 — CWE-20, CWE-22, CWE-78, CWE-79, CWE-89, CWE-90, CWE-95, CWE-113, CWE-117, CWE-126, CWE-190, CWE-201, CWE-209, CWE-256, CWE-295, CWE-321, CWE-327, CWE-330, CWE-338, CWE-346, CWE-347, CWE-352, CWE-362, CWE-377, CWE-384, CWE-489, CWE-502, CWE-506, CWE-532, CWE-601, CWE-611, CWE-614, CWE-639, CWE-643, CWE-681, CWE-759, CWE-798, CWE-862, CWE-915, CWE-918, CWE-942, CWE-943, CWE-1236, CWE-1321, CWE-1333, CWE-1336, CWE-1357
 
 ## How coverage is scored
 
@@ -35,6 +35,7 @@ counts as a detection. See `docs/SCANNER_INTEGRATION.md`.
 
 | Test case | File | CWE | Severity | Expected | Markers |
 |---|---|---|---|---|---|
+| Out-of-bounds read via unchecked array index | [`cwe-126-java.java`](../vulns/java/cwe-126-java.java) | CWE-126 | high | yes | 1 vuln / 1 safe |
 | Insecure deserialisation via ObjectInputStream | [`deserialization-object-input-stream.java`](../vulns/java/deserialization-object-input-stream.java) | CWE-502 | critical | yes | 2 vuln / 2 safe |
 | SQL injection via Statement string concatenation | [`sqli-statement-concat.java`](../vulns/java/sqli-statement-concat.java) | CWE-89 | critical | yes | 2 vuln / 1 safe |
 | Reflected XSS via HttpServletResponse writer | [`xss-response-writer.java`](../vulns/java/xss-response-writer.java) | CWE-79 | high | yes | 2 vuln / 2 safe |

diff --git a/vulns/VULNERABILITY_CATALOG.json b/vulns/VULNERABILITY_CATALOG.json
@@ -2,10 +2,10 @@
   "schema": "threatcrush-testbed-catalog/1",
   "note": "Generated by scripts/generate-catalog.py \u2014 do not edit by hand.",
   "totals": {
-    "test_cases": 62,
-    "expected_detections": 62,
-    "vulnerable_markers": 123,
-    "safe_markers": 73,
+    "test_cases": 63,
+    "expected_detections": 63,
+    "vulnerable_markers": 124,
+    "safe_markers": 74,
     "languages": [
       "dotenv",
       "go",
@@ -35,6 +35,7 @@
       "CWE-95",
       "CWE-113",
       "CWE-117",
+      "CWE-126",
       "CWE-190",
       "CWE-201",
       "CWE-209",
@@ -175,6 +176,29 @@
         56
       ]
     },
+    {
+      "id": "java-buffer-overread-array-index",
+      "file": "vulns/java/cwe-126-java.java",
+      "title": "Out-of-bounds read via unchecked array index",
+      "category": "java",
+      "language": "java",
+      "cwe": "CWE-126",
+      "cwes": [
+        "CWE-126"
+      ],
+      "severity": "high",
+      "expected_detection": true,
+      "description": "An attacker-controlled index is used to read from a byte array",
+      "detection_target": "Array read with attacker-controlled index without bounds",
+      "safe_guard": "Every payload is behind the always-false NEVER_RUN constant and",
+      "attribution": "line",
+      "vulnerable_lines": [
+        38
+      ],
+      "safe_lines": [
+        50
+      ]
+    },
     {
       "id": "java-deserialization-object-input-stream",
       "file": "vulns/java/deserialization-object-input-stream.java",

diff --git a/vulns/java/cwe-126-java.java b/vulns/java/cwe-126-java.java
@@ -0,0 +1,58 @@
+/**
+ * @id java-buffer-overread-array-index
+ * @test-case Out-of-bounds read via unchecked array index
+ * @cwe CWE-126
+ * @severity high
+ * @language java
+ * @expected-detection true
+ * @description An attacker-controlled index is used to read from a byte array
+ *              without bounds checking. If the index is negative or greater
+ *              than or equal to the array length, the read accesses memory
+ *              outside the intended buffer, potentially leaking sensitive
+ *              data or causing a crash. This is a classic buffer over-read
+ *              vulnerability.
+ * @safe-guard Every payload is behind the always-false NEVER_RUN constant and
+ *             the repository has no Java build file, so nothing is compiled.
+ *             No real data is accessed; the array is a local dummy buffer.
+ * @detection-target Array read with attacker-controlled index without bounds
+ *                   check.
+ *
+ * NEVER RUN IN PRODUCTION — intentional test case for scanner validation.
+ */
+package vulns.java;
+
+import javax.servlet.http.HttpServletRequest;
+
+public class BufferOverreadArrayIndex {
+
+    private static final boolean NEVER_RUN = false;
+
+    public byte readByteVulnerable(HttpServletRequest req) {
+        if (NEVER_RUN) {
+            byte[] buffer = new byte[16];
+            // Fill buffer with dummy data
+            for (int i = 0; i < buffer.length; i++) {
+                buffer[i] = (byte) i;
+            }
+            int index = Integer.parseInt(req.getParameter("idx")); // SOURCE
+            return buffer[index]; // VULNERABLE: CWE-126 sink
+        }
+        return 0;
+    }
+
+    public byte readByteSafe(HttpServletRequest req) {
+        if (NEVER_RUN) {
+            byte[] buffer = new byte[16];
+            for (int i = 0; i < buffer.length; i++) {
+                buffer[i] = (byte) i;
+            }
+            int index = Integer.parseInt(req.getParameter("idx"));
+            // SAFE: bounds check before access
+            if (index >= 0 && index < buffer.length) {
+                return buffer[index];
+            }
+            return -1;
+        }
+        return 0;
+    }
+}