CVE-2026-53753

[CVE catalog]

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.

Severity

Critical · CVSS 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Published

Jun 23, 2026, 7:17:07 PM UTC

Source

[NVD] · [CVE record]

EPSS

2.90% · Oct 27, 2026

{
  "package_releases": [],
  "fixed_versions": [],
  "distribution_packages": [
    {
      "name": "crawl4ai",
      "ecosystem": "cpe",
      "fixed_version": "0.8.7"
    },
    {
      "name": "crawl4ai",
      "ranges": [
        {
          "fixed": "0.8.7",
          "introduced": "",
          "last_affected": "",
          "start_excluding": ""
        }
      ],
      "ecosystem": "cpe",
      "fixed_version": "0.8.7",
      "provider_record_id": "NVD-CVE-2026-53753"
    }
  ]
}