{"id":"CVE-2026-53753","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-53753","generatedAt":"2026-10-28T03:25:18.857Z","title":"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.","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.","published":"2026-06-23T19:17:07.000Z","lastModified":"2026-10-25T23:10:00.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":10,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H"},"cwe":["CWE-94","CWE-913"],"affected":["kidocode/crawl4ai"],"epss":{"score":0.029,"percentile":0.86849,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (2.90%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7","tags":["Third Party Advisory","Mitigation"],"source":"security-advisories@github.com"},{"url":"https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7","tags":["Third Party Advisory","Mitigation"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-53753","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}