# Crawl4AI: AST Sandbox Escape via gi_frame.f_back Chain - Pre-Auth RCE in Docker API

Advisory record · `GHSA-qxjp-w3pj-48m7`

- **Identifiers:** `GHSA-qxjp-w3pj-48m7` · `CVE-2026-53753` · `PYSEC-2026-319`
- **State:** Confirmed
- **Severity:** CVSS 9.8 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-94](https://cwe.mitre.org/data/definitions/94.html) · [CWE-913](https://cwe.mitre.org/data/definitions/913.html)
- **Tags:** [Code injection](https://agentprime.io/advisories/tag/code-injection.md) · [CWE-913](https://agentprime.io/advisories/tag/cwe-913.md)
- **Published:** 16 Jun 2026
- **Updated:** 20 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 16 Jun 2026, 20:13 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.8: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `crawl4ai` (PyPI): affected `<0.8.7`; fixed in `0.8.7`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Crawl4AI versions before 0.8.7 are vulnerable to a sandbox escape in the computed fields feature of the Docker API: the AST validator fails to block generator and frame attributes such as gi_frame and f_back. An unauthenticated attacker, who needs no login because JWT is disabled by default, can send a crafted POST /crawl request and execute arbitrary commands in the container. Upgrade to version 0.8.7 or later; alternatively, enable JWT authentication via CRAWL4AI_API_TOKEN and restrict network access to the Docker API.

Written 5 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 9.8 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.029, the 86th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:42 UTC: First seen by agentprime
- 31 Oct 2026, 14:42 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-qxjp-w3pj-48m7)

## Sources

- [GitHub Advisory Database: GHSA-qxjp-w3pj-48m7](https://github.com/advisories/GHSA-qxjp-w3pj-48m7)
- [OSV: GHSA-qxjp-w3pj-48m7](https://osv.dev/vulnerability/GHSA-qxjp-w3pj-48m7)
- <https://github.com/unclecode/crawl4ai/security/advisories/GHSA-qxjp-w3pj-48m7>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-53753>
- <https://github.com/unclecode/crawl4ai/pull/1855>
- <https://github.com/unclecode/crawl4ai/pull/1886>
- <https://github.com/advisories/GHSA-qxjp-w3pj-48m7>
- <https://github.com/pypa/advisory-database/tree/main/vulns/crawl4ai/PYSEC-2026-319.yaml>
- <https://github.com/unclecode/crawl4ai>
- <https://pypi.org/project/crawl4ai>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-qxjp-w3pj-48m7>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-qxjp-w3pj-48m7/>. Everything for agents: <https://agentprime.io/llms.txt>.