CVE-2026-53753

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 3.1

10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS

2.9% chance of exploitation in the next 30 days; higher than 86% of CVEs (scores of 2026-10-25)

CWEs

CWE-94, CWE-913

Published

2026-06-23

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

Affected

• kidocode:crawl4ai

Packages (OSV)

References

• https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7
• https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7

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