CVE-2026-33693

CVE-2026-33693: SSRF via 0.0.0.0 Bypass in activitypub-federation-rust v4isinvalid CVSS 6.5 Moderate Keywords: SSRF, 0.0.0.0, IP validation bypass, activitypub-federation, Lemmy, Rust, ActivityPub Table of Contents Overview Vulnerability Details Technical Analysis Attack Chain Impact Remediation...

CVE-2026-33693 Lemmy's Activitypub-Federation has SSRF via 0.0.0.0 bypass in activitypub-federation-rust v4_is_invalid()

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,...

CVE-2026-33693: Server-Side Request Forgery (SSRF)

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...

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,...

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,...

📄 activitypub-federation-rust 0.7.1 Server-Side Request Forgery

activitypub-federation-rust versions 0.7.1 and below suffer from a server-side request forgery vulnerability. CVE-2026-33693: SSRF via 0.0.0.0 Bypass in activitypub-federation-rust v4isinvalid CVSS 6.5 Moderate Keywords: SSRF, 0.0.0.0, IP validation bypass, activitypub-federation, Lemmy, Rust,...