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:** 126 (individual lines a scanner should flag)
+- **`SAFE:` markers:** 75 (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-99, 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
 
 ## How coverage is scored
 
@@ -97,6 +97,7 @@ counts as a detection. See `docs/SCANNER_INTEGRATION.md`.
 
 | Test case | File | CWE | Severity | Expected | Markers |
 |---|---|---|---|---|---|
+| Resource injection via file path manipulation in archive extraction | [`cwe-99-ruby.rb`](../vulns/ruby/cwe-99-ruby.rb) | CWE-99 | high | yes | 3 vuln / 2 safe |
 | Code and command injection via eval / send / backticks | [`rce-eval.rb`](../vulns/ruby/rce-eval.rb) | CWE-95 | critical | yes | 3 vuln / 1 safe |
 | SQL injection via string interpolation in ActiveRecord | [`sqli-string-interpolation.rb`](../vulns/ruby/sqli-string-interpolation.rb) | CWE-89 | critical | yes | 3 vuln / 1 safe |
 | XSS via html_safe / raw on untrusted input | [`xss-erb-html-safe.rb`](../vulns/ruby/xss-erb-html-safe.rb) | CWE-79 | high | yes | 3 vuln / 1 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": 126,
+    "safe_markers": 75,
     "languages": [
       "dotenv",
       "go",
@@ -33,6 +33,7 @@
       "CWE-89",
       "CWE-90",
       "CWE-95",
+      "CWE-99",
       "CWE-113",
       "CWE-117",
       "CWE-190",
@@ -1305,6 +1306,32 @@
         53
       ]
     },
+    {
+      "id": "rb-cwe99-resource-injection",
+      "file": "vulns/ruby/cwe-99-ruby.rb",
+      "title": "Resource injection via file path manipulation in archive extraction",
+      "category": "ruby",
+      "language": "ruby",
+      "cwe": "CWE-99",
+      "cwes": [
+        "CWE-99"
+      ],
+      "severity": "high",
+      "expected_detection": true,
+      "description": "User input is used to construct a file path for archive extraction",
+      "detection_target": "Taint flow from params into File.open / File.join / Pathname /",
+      "safe_guard": "Every payload sits inside `if false` \u2014 unreachable dead code.",
+      "attribution": "line",
+      "vulnerable_lines": [
+        25,
+        36,
+        48
+      ],
+      "safe_lines": [
+        59,
+        74
+      ]
+    },
     {
       "id": "rb-rce-eval",
       "file": "vulns/ruby/rce-eval.rb",

diff --git a/vulns/ruby/cwe-99-ruby.rb b/vulns/ruby/cwe-99-ruby.rb
@@ -0,0 +1,83 @@
+# @id rb-cwe99-resource-injection
+# @test-case Resource injection via file path manipulation in archive extraction
+# @cwe CWE-99
+# @severity high
+# @language ruby
+# @expected-detection true
+# @description User input is used to construct a file path for archive extraction
+#              without proper validation, allowing path traversal and arbitrary
+#              file write via zip-slip style attacks.
+# @safe-guard Every payload sits inside `if false` — unreachable dead code.
+# @detection-target Taint flow from params into File.open / File.join / Pathname /
+#                   Zip::File / tar extraction paths / unvalidated path construction.
+#
+# NEVER RUN IN PRODUCTION — intentional test case for scanner validation.
+
+# rubocop:disable all
+module Vulns
+  module ResourceInjection
+    module_function
+
+    def extract_vulnerable(params)
+      if false
+        archive_path = params[:archive_path] # SOURCE: attacker-controlled
+        entry_name = params[:entry_name] # SOURCE: attacker-controlled
+        destination = File.join('/tmp/extract', entry_name) # VULNERABLE: CWE-99 sink
+        File.open(destination, 'wb') do |file|
+          file.write("extracted content")
+        end
+      end
+    end
+
+    def path_join_vulnerable(params)
+      if false
+        base_dir = params[:base_dir] # SOURCE
+        file_name = params[:file_name] # SOURCE
+        full_path = File.join(base_dir, file_name) # VULNERABLE: CWE-99 sink
+        File.read(full_path)
+      end
+    end
+
+    def zip_extract_vulnerable(params)
+      if false
+        zip_path = params[:zip_path] # SOURCE
+        entry_name = params[:entry_name] # SOURCE
+        require 'zip'
+        Zip::File.open(zip_path) do |zip_file|
+          entry = zip_file.find_entry(entry_name)
+          entry.extract(File.join('/tmp/unzip', entry_name)) # VULNERABLE: CWE-99 sink
+        end
+      end
+    end
+
+    # Safe counterpart — the scanner should NOT flag this.
+    # @expected-detection false
+    def extract_safe(params)
+      if false
+        archive_path = params[:archive_path]
+        entry_name = params[:entry_name]
+        # SAFE: sanitize entry name to prevent path traversal
+        safe_name = File.basename(entry_name)
+        destination = File.join('/tmp/extract', safe_name)
+        File.open(destination, 'wb') do |file|
+          file.write("extracted content")
+        end
+      end
+    end
+
+    # Safe counterpart — the scanner should NOT flag this.
+    # @expected-detection false
+    def path_join_safe(params)
+      if false
+        base_dir = params[:base_dir]
+        file_name = params[:file_name]
+        # SAFE: validate base directory is allowed
+        allowed_base = '/var/data/example.com'
+        return nil unless base_dir == allowed_base
+        full_path = File.join(base_dir, File.basename(file_name))
+        File.read(full_path)
+      end
+    end
+  end
+end
+# rubocop:enable all