Vulnerability Description
Crawl4AI is an open-source LLM friendly web crawler & scraper. Prior to 0.8.7, the _safe_eval_expression() function in the computed fields feature uses an AST validator that only blocks attributes starting with underscore. Python generator and frame object attributes (gi_frame, f_back, f_builtins) do NOT start with underscore, enabling a complete sandbox escape to achieve arbitrary code execution. The attack requires no authentication (JWT disabled by default) and is triggered via POST /crawl with a crafted extraction schema. This vulnerability is fixed in 0.8.7.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Kidocode | Crawl4Ai | < 0.8.7 |
Related Weaknesses (CWE)
References
- https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7Third Party AdvisoryMitigation
- https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7Third Party AdvisoryMitigation
FAQ
What is CVE-2026-53753?
CVE-2026-53753 is a vulnerability with a CVSS score of 9.8 (CRITICAL). Crawl4AI is an open-source LLM friendly web crawler & scraper. Prior to 0.8.7, the _safe_eval_expression() function in the computed fields feature uses an AST validator that only blocks attributes sta...
How severe is CVE-2026-53753?
CVE-2026-53753 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-53753?
Check the references section above for vendor advisories and patch information. Affected products include: Kidocode Crawl4Ai.