# Adversarial Bug Report: fix-dashboard-cors-origin

## Attack Vectors Tested
1. **Preflight OPTIONS request**: `do_OPTIONS()` returns 204 without CORS headers — browser will block cross-origin requests correctly
2. **Missing security headers on error responses**: `_send_error()` uses `SECURITY_HEADERS` — verified
3. **X-Frame-Options bypass**: `DENY` is the most restrictive value — no bypass
4. **MIME type confusion**: `X-Content-Type-Options: nosniff` prevents browsers from sniffing content type

## Findings
No bugs found. The security headers are correctly applied to all response types.

## Verdict: PASS