CVE-2026-33693

Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the v4isinvalid function in activitypub-federation-rust src/utils.rs does not check for Ipv4Addr::UNSPECIFIED 0.0.0.0. An unauthenticated attacker controlling a remote domain can point it to 0.0.0.0, bypass the...

CVE-2026-33693

Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the v4isinvalid function in activitypub-federation-rust src/utils.rs does not check for Ipv4Addr::UNSPECIFIED 0.0.0.0. An unauthenticated attacker controlling a remote domain can point it to 0.0.0.0, bypass the...

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...

GHSA-Q537-8FR5-CW35 Activitypub-Federation has SSRF via 0.0.0.0 bypass in activitypub-federation-rust v4_is_invalid()

Summary The v4isinvalid function in activitypub-federation-rust src/utils.rs does not check for Ipv4Addr::UNSPECIFIED 0.0.0.0. An unauthenticated attacker controlling a remote domain can point it to 0.0.0.0, bypass the SSRF protection introduced by the fix for CVE-2025-25194 GHSA-7723-35v7-qcxw,...