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CRITICAL severity

GHSA-qxjp-w3pj-48m7

CRITICALFix: unclecode/crawl4ai#1855

GHSA-qxjp-w3pj-48m7 is a critical-severity (CVSS 9.8) Code Injection vulnerability in crawl4ai. O3 Security confirms whether GHSA-qxjp-w3pj-48m7 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

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

Also known asCVE-2026-53753PYSEC-2026-319
Published
Jun 16, 2026
Updated
Jul 20, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Aug 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for GHSA-qxjp-w3pj-48m7.

EPSS Exploitation Probability

via FIRST.org ↗
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs46th percentile — riskier than 46% of all scored CVEsHighest risk
0.00%0.37%0.74%1.11%0.4%0.6%0.6%Jul 26Aug 26Aug 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-qxjp-w3pj-48m7 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
🐍crawl4ai

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

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.

Attack Vector

An attacker sends a POST /crawl request with a JsonCssExtractionStrategy schema containing a malicious computed field expression that:

  1. Creates a generator to access gi_frame
  2. Walks the frame chain via f_back
  3. Reaches f_builtins containing the real __import__
  4. Imports os and executes arbitrary commands

Impact

Unauthenticated remote code execution inside the Docker container. An attacker can execute arbitrary system commands, read/write files, and exfiltrate secrets.

Fix Details

  1. Removed eval() from computed field expression path entirely -- expressions now log a warning and return default value
  2. Deleted _safe_eval_expression() function and _SAFE_EVAL_BUILTINS (dead security-sensitive code)
  3. function key with Python callables still works for SDK users
  4. Replaced eval() in /config/dump with JSON-based input validated by Pydantic
  5. Fixed hook_manager sandbox: stripped __builtins__, __loader__, __spec__ from injected modules; removed getattr, setattr, type, __build_class__ from allowed builtins

Workarounds

  1. Upgrade to the patched version (recommended)
  2. Enable JWT authentication via CRAWL4AI_API_TOKEN environment variable
  3. Restrict network access to the Docker API

Credits

  • Song Binglin (q1uf3ng) - reported the AST sandbox escape
  • by111 (August829) - reported the hook sandbox __builtins__ escape and hardcoded JWT secret bypass
  • jannahopp - PR #1855 proposing eval removal
  • ntohidi - PR #1886 proposing allowlist approach

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIcrawl4aiall versions0.8.7

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for crawl4ai. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update crawl4ai to 0.8.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qxjp-w3pj-48m7 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-qxjp-w3pj-48m7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-qxjp-w3pj-48m7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary 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. ### Attack Vector An attacker sends a `POST /crawl` request with a `JsonCssExtractionStrategy` schema containing a malici
O3 Security · Impact-Aware SCA

Is GHSA-qxjp-w3pj-48m7 in your dependencies?

O3 detects GHSA-qxjp-w3pj-48m7 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.