CVE-2026-33693

Lemmy’s Activitypub-Federation vulnerable component: Rust-based v4_is_invalid() in activitypub_federation-rust fails to check IPv4Addr::UNSPECIFIED (0.0.0.0). An unauthenticated attacker controlling a remote domain could direct 0.0.0.0 and bypass SSRF protections, reaching localhost services on t...