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.
CVE-2026-53753
CRITICALNVD 10.010.0—
EchelonGraph scoreMEDIUM confidence
This critical-severity CVE scores 10.0 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 64% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, nvd
10.0
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 10.0Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 10.0
- EG Score
- 10.0(medium)
- EPSS
- 36.1%
- KEV
- Not listed
Published
June 16, 2026
Last Modified
June 29, 2026
Advisory Details (1)
Auto-updated Jul 7, 2026Patch available. Sources: github.
github Patch Available
AST Sandbox Escape via gi_frame.f_back Chain - Pre-Auth RCE in Docker API · Advisory · unclecode/crawl4ai · GitHub
https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7Vendor Advisories for CVE-2026-53753(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| crawl4ai | 0.3.0 ... 0.8.6 (64 versions) | 0.8.7 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Related CVEs(same CWE)
Same CWE
10 shownCWE-94
- CVE-2006-1359NVD 0.0EG 9.0EPSS 99%NONE
- CVE-2005-1921NVD 0.0EG 9.0EPSS 100%NONE
- CVE-2005-3302EG 7.3HIGH
- CVE-2005-1876EG 4.5MEDIUM
- CVE-2003-1599EG 0.0NONE
- CVE-2006-1318EG 0.0EPSS 96%NONE
- CVE-2006-1301EG 0.0EPSS 95%NONE
- CVE-2006-1308EG 0.0EPSS 95%NONE
- CVE-2006-1309EG 0.0EPSS 95%NONE
- CVE-2006-1304EG 0.0EPSS 95%NONE
Frequently asked(5)
What is CVE-2026-53753?
CVE-2026-53753 is a critical vulnerability published on June 16, 2026. Crawl4AI is an open-source LLM friendly web crawler & scraper. Prior to 0.8.7, the safeevalexpression() function in the computed fields feature uses an AST validator that only blocks attributes starting with underscore. Python generator and frame object attributes (giframe, fback, fbuiltins) do NOT…
When was CVE-2026-53753 disclosed?
CVE-2026-53753 was first published in the National Vulnerability Database on June 16, 2026, with the most recent update on June 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53753 actively exploited?
CVE-2026-53753 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 36.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-53753?
CVE-2026-53753 has a CVSS v3 base score of 10.0 (NVD).
How do I remediate CVE-2026-53753?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53753, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53753
Is Your Infrastructure Affected by CVE-2026-53753?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.