test: add xxe-lxml-resolve fixture (CWE-611)

docs/VULNERABILITY_CATALOG.md

@@ -7,10 +7,10 @@ from each file's header comment, so this page cannot drift from the source.
 
 ## Totals
 
-- **Test cases:** 116
-- **Expected detections:** 116
-- **`VULNERABLE:` markers:** 215 (individual lines a scanner should flag)
-- **`SAFE:` markers:** 131 (lines a scanner must not flag — the false-positive control group)
+- **Test cases:** 117
+- **Expected detections:** 117
+- **`VULNERABLE:` markers:** 217 (individual lines a scanner should flag)
+- **`SAFE:` markers:** 132 (lines a scanner must not flag — the false-positive control group)
 - **Languages:** 8 — dotenv, go, java, javascript, json, python, ruby, text
 - **CWE categories:** 84 — CWE-20, CWE-22, CWE-78, CWE-79, CWE-89, CWE-90, CWE-94, CWE-95, CWE-113, CWE-117, CWE-129, CWE-190, CWE-201, CWE-203, CWE-208, CWE-209, CWE-256, CWE-287, CWE-288, CWE-291, CWE-295, CWE-306, CWE-307, CWE-319, CWE-321, CWE-326, CWE-327, CWE-329, CWE-330, CWE-338, CWE-345, CWE-346, CWE-347, CWE-352, CWE-362, CWE-377, CWE-384, CWE-400, CWE-434, CWE-441, CWE-460, CWE-472, CWE-475, CWE-480, CWE-488, CWE-489, CWE-502, CWE-506, CWE-509, CWE-512, CWE-521, CWE-525, CWE-532, CWE-598, CWE-601, CWE-602, CWE-611, CWE-613, CWE-614, CWE-620, CWE-639, CWE-640, CWE-643, CWE-681, CWE-693, CWE-732, CWE-759, CWE-776, CWE-798, CWE-835, CWE-862, CWE-863, CWE-915, CWE-916, CWE-918, CWE-922, CWE-942, CWE-943, CWE-1021, CWE-1236, CWE-1321, CWE-1333, CWE-1336, CWE-1357
 
@@ -145,6 +145,7 @@ counts as a detection. See `docs/SCANNER_INTEGRATION.md`.
 | XML parser accepts external / inline entity expansion | [`xml-entity-expansion.py`](../vulns/python/xml-entity-expansion.py) | CWE-776 | high | yes | 6 vuln / 0 safe |
 | XPath injection via string interpolation | [`xpath-injection.py`](../vulns/python/xpath-injection.py) | CWE-643 | high | yes | 1 vuln / 1 safe |
 | XSS via Jinja2 autoescape disabled and server-side template injection | [`xss-jinja2-autoescape-off.py`](../vulns/python/xss-jinja2-autoescape-off.py) | CWE-79 | high | yes | 3 vuln / 1 safe |
+| XML external entity expansion in an insecure parser | [`xxe-lxml-resolve.py`](../vulns/python/xxe-lxml-resolve.py) | CWE-611 | high | yes | 2 vuln / 1 safe |
 
 ## Ruby
 

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": 116,
-    "expected_detections": 116,
-    "vulnerable_markers": 215,
-    "safe_markers": 131,
+    "test_cases": 117,
+    "expected_detections": 117,
+    "vulnerable_markers": 217,
+    "safe_markers": 132,
     "languages": [
       "dotenv",
       "go",
@@ -2600,6 +2600,30 @@
         53
       ]
     },
+    {
+      "id": "py-xxe-lxml-resolve",
+      "file": "vulns/python/xxe-lxml-resolve.py",
+      "title": "XML external entity expansion in an insecure parser",
+      "category": "python",
+      "language": "python",
+      "cwe": "CWE-611",
+      "cwes": [
+        "CWE-611"
+      ],
+      "severity": "high",
+      "expected_detection": true,
+      "description": "A parser is configured to resolve external entities while the",
+      "detection_target": "lxml etree.XMLParser with resolve_entities=True, or",
+      "safe_guard": "Every call is wrapped in `if False:` (unreachable dead code). No",
+      "attribution": "line",
+      "vulnerable_lines": [
+        30,
+        31
+      ],
+      "safe_lines": [
+        42
+      ]
+    },
     {
       "id": "rb-cwe480-credential-comparison",
       "file": "vulns/ruby/cwe-480-ruby.rb",

vulns/python/xxe-lxml-resolve.py

@@ -0,0 +1,45 @@
+"""
+@id py-xxe-lxml-resolve
+@test-case XML external entity expansion in an insecure parser
+@cwe CWE-611
+@severity high
+@language python
+@expected-detection true
+@description A parser is configured to resolve external entities while the
+             document being parsed comes from an untrusted request. With entity
+             resolution on, a crafted payload can read local files (file://),
+             probe internal hosts, or exhaust memory. The safe counterpart
+             disables external entity access entirely. Detection target is the
+             parser configuration flag (resolve_entities / load_dtd) rather than
+             any specific external host, so the fixture carries no host literal
+             at all.
+@safe-guard Every call is wrapped in `if False:` (unreachable dead code). No
+            document is parsed, no file is opened, and the entity URL, if any,
+            would point at an unresolvable `.invalid` host. The fixture only
+            demonstrates the parser construction.
+@detection-target lxml etree.XMLParser with resolve_entities=True, or
+                  XMLParser/xml.sax creation with entity resolution enabled
+                  where the source document is untrusted.
+
+NEVER RUN IN PRODUCTION - intentional test case for scanner validation.
+"""
+
+
+def parse_signup_xml(raw_xml: bytes) -> dict:
+    if False:
+        parser = etree.XMLParser(resolve_entities=True)  # VULNERABLE: CWE-611 - enables XXE
+        root = etree.fromstring(raw_xml, parser=parser)  # VULNERABLE: CWE-611 - untrusted doc hits the XInclude/entity resolver
+        return {"name": root.findtext("name") or ""}
+    return {}
+
+
+def parse_signup_xml_safe(raw_xml: bytes) -> dict:
+    """Safe counterpart - the scanner should NOT flag this.
+
+    @expected-detection false
+    """
+    if False:
+        parser = etree.XMLParser(resolve_entities=False, load_dtd=False)  # SAFE: entity resolution disabled
+        root = etree.fromstring(raw_xml, parser=parser)
+        return {"name": root.findtext("name") or ""}
+    return {}