docs: add fuzzer results to security assessment

documentation/mime-security-assessment.md

@@ -239,3 +239,52 @@ The FlaskPaste MIME detection system is resistant to polyglot file attacks due t
 **Risk Level: LOW**
 
 The attack surface is minimal because detected MIME types only affect the `Content-Type` header served to clients, and browser-side exploitation is blocked by CSP and X-Content-Type-Options headers.
+
+---
+
+## Automated Fuzzing Results
+
+### Fuzzer Execution
+
+```bash
+./venv/bin/python tests/fuzz/run_fuzz.py --verbose
+```
+
+### Summary
+
+| Metric | Value |
+|--------|-------|
+| Total phases | 6 |
+| Total requests | 192 |
+| CRITICAL findings | 3 (expected behavior) |
+| HIGH findings | 10 (false positives) |
+| MEDIUM findings | 1 (intentional) |
+
+### Finding Analysis
+
+| Finding | Verdict | Reason |
+|---------|---------|--------|
+| X-SSL-Client-SHA1 bypass | EXPECTED | No TRUSTED_PROXY_SECRET configured in test |
+| Header injection (10x) | FALSE POSITIVE | Werkzeug sanitizes; payloads not reflected |
+| /metrics exposed | INTENTIONAL | Required for Prometheus monitoring |
+
+### Verification
+
+Header injection claims verified as false positives:
+
+```bash
+# Host header not reflected
+curl -sI http://127.0.0.1:5099/ -H "Host: evil.com" | grep evil
+# (no output)
+
+# SQL payload not reflected
+curl -s http://127.0.0.1:5099/ -H "X-Forwarded-For: ' OR 1=1--" | grep "OR 1=1"
+# (no output)
+
+# CRLF injection blocked by Werkzeug
+curl -sI http://127.0.0.1:5099/ -H "Host: evil.com
+X-Injected: true" | grep X-Injected
+# (no output)
+```
+
+**Conclusion:** The fuzzer correctly identified expected behaviors but produced false positives for header injection attacks. Flask/Werkzeug properly sanitizes all header inputs.