CVE-2026-53754

Description

### Summary 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. ### Affected paths The blocklist was applied to crawl URLs (`POST /crawl`, `/md`, `/html`, `/screenshot`, `/pdf`, `/execute_js`) and webhook URLs (`/crawl/job`, `/llm/job`). All shared the same incomplete check. ### Bypasses The following all resolve to (or route to) blocked internal addresses but were NOT caught: - IPv6 unspecified `::` - NAT64 `64:ff9b::a9fe:a9fe` (embeds `169.254.169.254`) - 6to4 `2002:a9fe:a9fe::` (embeds `169.254.169.254`) - IPv4-mapped `::ffff:169.254.169.254` - IPv4-compatible `::a9fe:a9fe` The error message also echoed the resolved internal IP, acting as a minor DNS/oracle leak. ### Impact Server-Side Request Forgery: an unauthenticated attacker can make the server fetch internal-network URLs and cloud instance-metadata endpoints, potentially exposing internal services and cloud credentials. ### Fix The blocklist is replaced by a single rule: reject any resolved IP where `not ip.is_global`, evaluated on the address AND every embedded IPv4 transition form (v4-mapped, NAT64 `64:ff9b::/96`, 6to4 `2002::/16`, v4-compat `::/96`). Error messages are now opaque and no longer echo the resolved IP. ### Workarounds - Upgrade to the patched version. - Enable authentication (`CRAWL4AI_API_TOKEN`). - Restrict the container's outbound network access (egress firewall / no metadata route). ### Credits Internal security audit (Crawl4AI maintainers).

How to fix CVE-2026-53754

To remediate CVE-2026-53754, upgrade the affected package to a fixed version below.

• —upgrade to 0.8.8 or later

Is CVE-2026-53754 being exploited?

No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-53754.