CVE-2026-53753

critical

Crawl4AI is an open-source LLM friendly web crawler & scraper.

Vendor / product: Kidocode — crawl4ai

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

10.0

10.0 (CVSS v3.1)

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

Severity source: NVD CVSS v3.1 (nvd@nist.gov)

Timeline (UTC)

Published: 2026-06-23 19:17

Modified: 2026-10-25 23:10

NVD status: Analyzed

Last synced 2 days ago

Verified against the source API 2026-10-27 07:07 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

kidocode / crawl4ai <0.8.7

Weakness classification (CWE)

CWE-94 CWE-913

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

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

References

https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7 security-advisories@github.com
https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7 134c704f-9b21-4f2e-91b3-4a467353bcc0

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 07:07 UTC · record ↗

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