CVE-2026-53753
CRITICAL 10.0EPSS 2.9%
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 v3.1
- 10.0 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - CVSS v3.1
- 9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS v3.1
- 9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 2.90% chance of exploitation in the next 30 days, 86th percentile
- Nuclei
- critical · CWE-94
- Published
- 2026-06-23
Proof-of-concept exploits (2)
- 0xEnc0der/CVE-2026-537530★ · 2026-07-02
- BiiTts/CVE-2026-53753-Crawl4AI-RCE