Vulnerability details
CVE-2026-53753
unclecode Crawl4AI
Crawl4AI: AST Sandbox Escape via gi_frame.f_back Chain - Pre-Auth RCE in Docker API
CVSS 3.1
9.8Critical
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.8Critical | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| unclecode | Crawl4AI | < 0.8.7 | CVEProject cvelistV5 (CNA) |
References and advisories
1- https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7 x_refsource_CONFIRM
Kolun on Telegram @kolunsec
Exploited CVEs, key news and a daily digest
Alerts for this product's next CVEsFollow the product to get new vulnerabilities on Telegram.
Details
- Published
- 2026-06-23
- Last updated
- 2026-06-23
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
2.9%
Probability of exploitation in 30 days
86.9%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- Proof of concept
- Technical impact
- Total
Weaknesses (CWE)
- CWE-94Improper Control of Generation of Code ('Code Injection')
- CWE-913Improper Control of Dynamically-Managed Code Resources