CVE-2025-25194: Lemmynet Lemmy

Medium severity, CVSS 4.0. EPSS: 0.4% chance of exploitation in the next 30 days.

Lemmy, a link aggregator and forum for the fediverse, is vulnerable to server-side request forgery via a dependency on activitypub_federation, a framework for ActivityPub federation in Rust. This vulnerability, which is present in versions 0.6.2 and prior of activitypub_federation and versions 0.19.8 and prior of Lemmy, allows a user to bypass any predefined hardcoded URL path or security anti-Localhost mechanism and perform an arbitrary GET request to any Host, Port and URL using a Webfinger Request. As of time of publication, a fix has not been made available.

Affected products

• Lemmynet Lemmy: up to and including 0.19.8

Published 2025-02-10. Last modified 2026-06-17.