CVE-2026-29178: Lemmynet Lemmy

High severity, CVSS 7.7. 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. Prior to version 0.19.16, the GET /api/v4/image/{filename} endpoint is vulnerable to unauthenticated SSRF through parameter injection in the file_type query parameter. An attacker can inject arbitrary query parameters into the internal request to pict-rs, including the proxy parameter which causes pict-rs to fetch arbitrary URLs. This issue has been patched in version 0.19.16.

Affected products

• Lemmynet Lemmy: before 0.19.16 (fixed in 0.19.16)

Published 2026-03-06. Last modified 2026-06-17.