CVE-2026-54742
Lemmy is a link aggregator and forum for the fediverse. From 0.19.18 until 0.19.19 and 1.0.0-alpha.20, a community moderator can feature or unfeature posts in other communities through federated CollectionAdd and CollectionRemove activities using CollectionType::Featured. After verify_mod_action authorizes the actor against self.community(), the receive handlers in crates/apub/activities/src/community/collection_add.rs and crates/apub/activities/src/community/collection_remove.rs dereference self.object as an ApubPost and update featured_community without verifying that post.community_id equals community.id. A moderator can therefore target an unrelated post owned by another community, push it into featured feeds and listings, or undo another community's legitimate curation decision. This issue is fixed in versions 0.19.19 and 1.0.0-alpha.20.
- Affected products
- Lemmy
- CVSS 4.0
- 5.1 MEDIUM
- EPSS
- 0.4% (35th percentile)
- Weakness
- CWE-863
- NVD status
- Received
- Published
- 2026-08-19
No indexed exploits for CVE-2026-54742 yet
Our index is partial: it proves presence, never absence
No exploit for CVE-2026-54742 has been indexed yet. Our index is built from live traffic and upstream syncs, so this page can only say what it knows — not that no exploit exists.