# CVE-2026-53753

## Summary

- **CVE ID:** CVE-2026-53753
- **Severity:** CRITICAL
- **CVSS Score:** 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** CWE-94, CWE-913
- **Published:** Jun 23, 2026
- **Last Modified:** Jun 23, 2026

## 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.

## Affected Products

- unclecode — crawl4ai (< 0.8.7)

## References

- [CNA](https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 2.90%
- **EPSS Percentile:** 86.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._