{"id":"GHSA-2jq4-q6vv-4cp3","summary":"Crawl4AI: Arbitrary file write (path traversal) in crawler downloads can lead to RCE","details":"### Summary\n\nWhen the crawler saves a downloaded file, the destination filename was taken from attacker-influenced input and joined to the downloads directory with no confinement. A filename containing an absolute path (e.g. `/etc/cron.d/evil`) or `../` traversal escaped the downloads directory, giving an arbitrary file write with attacker-controlled contents. Because the written bytes are attacker-controlled, this escalates to remote code execution (overwriting a shell rc-file, `~/.ssh/authorized_keys`, a cron entry, or a Python module on the import path).\n\n### Affected paths\n\nTwo download sinks in `crawl4ai/async_crawler_strategy.py`:\n- HTTP crawler (`AsyncHTTPCrawlerStrategy`): the filename is parsed from the response `Content-Disposition` header by `_extract_filename()` and written via `aiofiles.open(filepath, 'wb')`. Reachable directly via the SDK, and via the unauthenticated Docker `/crawl` endpoint when an `HTTPCrawlerConfig` is supplied.\n- Browser crawler (`AsyncPlaywrightCrawlerStrategy`): the download's `suggested_filename` (controllable by the visited page) is joined to `downloads_path` and written via `download.save_as()`.\n\nThe HTTP-strategy sink is reachable pre-auth on the default Docker deployment; both are reachable for SDK users simply by crawling an attacker-controlled URL. The default Playwright crawl path that does not trigger a download is unaffected.\n\n### Impact\n\nArbitrary file write with attacker-controlled content as the user running the crawler, escalating to remote code execution.\n\n### Fix\n\nBoth sinks now resolve the destination through a single hardened helper (`_safe_download_filepath`) that reduces the attacker-influenced name to a bare basename (dropping absolute paths and `..` components) and re-checks, via `realpath`, that the resolved path stays inside the downloads root (defeating symlink/TOCTOU escapes). A traversal attempt is rejected; normal downloads are unchanged.\n\n### Workarounds\n\n- Upgrade to the patched version (0.9.0).\n- Run the crawler as an unprivileged user with a dedicated, isolated downloads directory on a volume with no sensitive paths writable.\n- Enable authentication (`CRAWL4AI_API_TOKEN`) on the Docker server.\n\n### Credits\n\nY4tacker - reported the Content-Disposition path traversal in the HTTP crawler with a clear PoC and a basename + realpath-containment fix recommendation.","aliases":["CVE-2026-57571","PYSEC-2026-2138"],"modified":"2026-07-13T07:26:47.459995537Z","published":"2026-06-18T17:25:13Z","database_specific":{"cwe_ids":["CWE-22","CWE-59"],"severity":"CRITICAL","github_reviewed":true,"github_reviewed_at":"2026-06-18T17:25:13Z","nvd_published_at":null},"references":[{"type":"WEB","url":"https://github.com/unclecode/crawl4ai/security/advisories/GHSA-2jq4-q6vv-4cp3"},{"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":"0.9.0"}]}],"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","0.8.9"],"database_specific":{"last_known_affected_version_range":"\u003c= 0.8.9","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-2jq4-q6vv-4cp3/GHSA-2jq4-q6vv-4cp3.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H"}]}