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OpenAdvisories
High · 7.5 CVE-2026-53754 EUVD-2026-38568GHSA-4qqr-vv2q-cmr5PYSEC-2026-587

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

Published Jun 23, 2026 · Updated Jun 23, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
unclecode crawl4ai < 0.8.8 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI crawl4ai < 0.8.8 0.8.8 GHSA-4qqr-vv2q-cmr5

References