PT-2026-50164 · Pypi · Crawl4Ai
Published
2026-06-16
·
Updated
2026-06-17
·
CVE-2026-53753
CVSS v3.1
9.8
Critical
| Vector | AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Name of the Vulnerable Software and Affected Versions
Crawl4AI versions prior to 0.8.7
Description
The
safe eval expression() function in the computed fields feature uses an AST (Abstract Syntax Tree) validator that only blocks attributes starting with an underscore. Because Python generator and frame object attributes such as gi frame, f back, and f builtins do not start with an underscore, they can be used to escape the sandbox and achieve arbitrary code execution. An unauthenticated attacker can trigger this by sending a 'POST /crawl' request with a crafted JsonCssExtractionStrategy schema containing a malicious computed field expression. This allows the attacker to access the frame chain, reach f builtins to import the os module, and execute arbitrary system commands inside the Docker container, potentially leading to file system access and secret exfiltration.Recommendations
Update to version 0.8.7.
Enable JWT authentication via the
CRAWL4AI API TOKEN environment variable.
Restrict network access to the Docker API.Fix
Code Injection
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Related Identifiers
Affected Products
Crawl4Ai