{"id":"GHSA-6qhc-x826-342c","summary":"Crawl4AI: SSRF via proxy settings in the Docker server bypasses the crawl-URL SSRF check","details":"### Summary\n\nThe Docker API server applied its SSRF destination check to the crawl target URL only, not to the proxy address. An unauthenticated request could supply a proxy pointing at an internal IP and route the browser through it, reaching internal services and cloud-metadata endpoints, while using a perfectly valid crawl URL. The Docker API is unauthenticated by default.\n\n### Affected paths\n\n`/crawl`, `/crawl/stream`, and `/crawl/job` accept a `browser_config` (and `crawler_config`). The following all feed Chromium's egress and were unchecked:\n- `browser_config.proxy_config.server`\n- `browser_config.proxy` (deprecated field)\n- `crawler_config.proxy_config.server`\n- `--proxy-server` / `--proxy-pac-url` / `--proxy-bypass-list` / `--host-resolver-rules` flags in `browser_config.extra_args`\n\n### Attack\n\nAn attacker sends `/crawl` with a benign, validation-passing URL but a `proxy_config.server` pointing at an internal IP. Chromium routes all requests through that proxy. For plain-HTTP targets the proxy receives the full request and can return any content, which is then returned verbatim in the crawl result (`results[0].html` / `cleaned_html` / `markdown`). In a real deployment the proxy would be an attacker-controlled server pointing at cloud metadata (e.g. AWS IMDSv1 at 169.254.169.254) to retrieve IAM credential tokens.\n\n### Impact\n\nUnauthenticated server-side request forgery to internal services and cloud-metadata endpoints, with the response returned to the attacker.\n\n### Fix\n\nEvery proxy destination is validated with the same global-routability check used for crawl URLs (reject any resolved address that is not `is_global`, including IPv6 transition forms) before the browser is constructed; proxy/DNS-redirecting flags are stripped from `extra_args`. A legitimate public proxy still works. Honors `CRAWL4AI_ALLOW_INTERNAL_URLS`.\n\n### Workarounds\n\n- Upgrade to the patched version (0.8.9).\n- Enable authentication (`CRAWL4AI_API_TOKEN`).\n- Restrict the container's outbound network access (egress firewall / no metadata route).\n\n### Credits\n\nGeo ([geo-chen](https://github.com/geo-chen)) - reported the proxy_config.server SSRF with a clear PoC.","aliases":["CVE-2026-53755","PYSEC-2026-588"],"modified":"2026-07-20T21:30:33.098890697Z","published":"2026-06-16T21:02:55Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-06-16T21:02:55Z","nvd_published_at":"2026-06-23T19:17:07Z","cwe_ids":["CWE-918"],"severity":"HIGH"},"references":[{"type":"WEB","url":"https://github.com/unclecode/crawl4ai/security/advisories/GHSA-6qhc-x826-342c"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53755"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/crawl4ai/PYSEC-2026-588.yaml"},{"type":"PACKAGE","url":"https://github.com/unclecode/crawl4ai"}],"affected":[{"package":{"name":"crawl4ai","ecosystem":"PyPI","purl":"pkg:pypi/crawl4ai"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.8.9"}]}],"versions":["0.3.0","0.3.1","0.3.2","0.3.3","0.3.4","0.3.5","0.3.6","0.3.7","0.3.71","0.3.72","0.3.73","0.3.731","0.3.74","0.3.741","0.3.742","0.3.743","0.3.744","0.3.745","0.3.746","0.3.8","0.4.0","0.4.1","0.4.21","0.4.22","0.4.23","0.4.24","0.4.241","0.4.242","0.4.243","0.4.244","0.4.245","0.4.246","0.4.247","0.4.248","0.4.248b3","0.4.3b1","0.4.3b2","0.4.3b3","0.5.0","0.5.0.post1","0.5.0.post2","0.5.0.post3","0.5.0.post4","0.5.0.post5","0.5.0.post6","0.5.0.post7","0.5.0.post8","0.6.0","0.6.0rc1","0.6.1","0.6.2","0.6.3","0.7.0","0.7.1","0.7.2","0.7.3","0.7.4","0.7.5","0.7.6","0.7.7","0.7.8","0.8.0","0.8.5","0.8.6","0.8.7","0.8.8"],"database_specific":{"last_known_affected_version_range":"\u003c= 0.8.8","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-6qhc-x826-342c/GHSA-6qhc-x826-342c.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N"}]}