Cloudanix VulnDB

CVE-2026-53753

Critical · 9.8

CVSS

9.8

EPSS

2.9%

Published

Jun 23, 2026

CISA due date

—

The record

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.

Affected packages

Ecosystem Package Introduced Fixed

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