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 v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7	Third Party Advisory Mitigation
https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7	Third Party Advisory Mitigation

Configurations

Configuration 1 (hide)

cpe:2.3:a:kidocode:crawl4ai:*:*:*:*:*:*:*:*

History

25 Oct 2026, 23:10

Type	Values Removed	Values Added
Summary		(es) Crawl4AI es un rastreador y extractor web de código abierto compatible con LLM. Antes de la versión 0.8.7, la función _safe_eval_expression() en la característica de campos calculados utiliza un validador AST que solo bloquea atributos que comienzan con guion bajo. Los atributos de objeto de generador y de marco de Python (gi_frame, f_back, f_builtins) NO comienzan con guion bajo, lo que permite un escape completo del sandbox para lograr ejecución de código arbitrario. El ataque no requiere autenticación (JWT deshabilitado por defecto) y se activa a través de POST /crawl con un esquema de extracción manipulado. Esta vulnerabilidad está corregida en 0.8.7.

Information

Published : 2026-06-23 19:17

Updated : 2026-10-25 23:10

NVD link : CVE-2026-53753

Mitre link : CVE-2026-53753

CVE.ORG link : CVE-2026-53753

JSON object : View

Products Affected

kidocode

crawl4ai

CWE

CWE-94

Improper Control of Generation of Code ('Code Injection')

CWE-913

Improper Control of Dynamically-Managed Code Resources

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