CVE Wiki Pixee · CVE intelligence
← All CVEs

CVE-2026-53753

Critical · CVSS 9.8

Crawl4AI — AST sandbox escape leading to arbitrary code execution (CWE-94, CWE-913)

CVSS
9.8
nvd
EPSS
0.45%
36th pct
KEV
No
Class
other
CWE-94, CWE-913

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.

Search profile — drives PoC discovery

Symbols _safe_eval_expressiongi_framef_backf_builtinscomputed fieldsextraction schemaPOST /crawl
Keywords CVE-2026-53753Crawl4AIsandbox escape_safe_eval_expressionAST bypassgi_framef_builtinsf_backarbitrary code executionPOST /crawlextraction schemaGHSA-qxjp-w3pj-48m7computed fields RCEcrawl4ai exploit
Versions: < 0.8.7

Ranked PoCs (2) — best first

Heuristic ranking — not yet expert-vetted. Scored on structure + provenance, not execution.

Recall-favoring discovery; ranking by the Stage-4 scorer (Adam's rubric). Scanner/aggregator repos are hidden.

References

Status: enriched · ingested 2026-06-29T18:00:49.000Z · profiled 2026-07-01T18:30:14.000Z