AIKIDO-2026-11097

TL;DR

The validatePublicUrl() function in the document loader applies an incomplete denylist of non-public IP ranges when validating remote URLs. Special-use IPv4 ranges such as shared address space, benchmarking, multicast, reserved, and documentation ranges, and IPv6 translation and tunneling prefixes such as NAT64, Teredo, and 6to4 are not rejected, so a URL pointing at these addresses passes the public-address check. Because the check runs before fetching remote ActivityPub documents and keys, an attacker who can influence a fetched URL can bypass the private-network protection and reach internal or special-use network resources. The fix replaces the checks with CIDR-based matching that rejects these special-use IPv4 ranges and IPv6 tunneling prefixes.