CVE-2026-53753
CriticalPublic exploitCrawl4AI: AST Sandbox Escape via gi_frame.f_back Chain - Pre-Auth RCE in Docker API
Published Jun 16, 2026 · Updated Aug 12, 2026 · Also known as EUVD-2026-38569, GHSA-qxjp-w3pj-48m7, PYSEC-2026-319
Key Facts
Patch immediately- CVE-2026-53753 is a critical-severity vulnerability (CVSS 10.0 v3.1) affecting Crawl4AI (Kidocode).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 2.9% probability of exploitation in the next 30 days.
- Fixed versions are available, including Crawl4AI 0.8.7.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
CVSS v3.1
10.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
2.9%
Higher than 86.7% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2026-53753 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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
3 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Crawl4AIKidocode | See advisory | 0.8.7 |
Patched Releases
Crawl4AI
0.8.7
Timeline
Publicly disclosed
Jun 16, 2026
Last updated
Aug 12, 2026
Weakness Type
- CWE-94 Improper Control of Generation of Code ('Code Injection')
- CWE-913 Improper Control of Dynamically-Managed Code Resources
References
- advisoryGHSA advisory
- advisoryhttps://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53753.json
- advisoryhttps://github.com/pypa/advisory-database/tree/main/vulns/crawl4ai/PYSEC-2026-319.yaml
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-53753
- articlehttps://github.com/unclecode/crawl4ai/pull/1855
FAQ
Common Questions.
Crawl4AI is an open-source LLM friendly web crawler & scraper.
Affected: Crawl4AI (Kidocode). The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Crawl4AI 0.8.7.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
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