CVE-2026-54740

In Lemmy versions prior to 0.19.19 and 1.0.0-alpha.18, the federated ActivityPub handler CollectionRemove::receive in crates/apub/activities/src/community/collection_remove.rs omits the rank check (is_higher_mod_or_admin_check) enforced by the local API, allowing any signed ActivityPub Remove act...

CVE-2026-54740 Lemmy: Lower-ranked federated moderator can remove higher-ranked moderators

Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, a lower-ranked remote moderator can remove a higher-ranked moderator by sending a signed ActivityPub Remove activity to the target instance. The local API uses LocalUser::ishighermodoradmincheck to enforc...

EUVD-2026-62844

Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, a lower-ranked remote moderator can remove a higher-ranked moderator by sending a signed ActivityPub Remove activity to the target instance. The local API uses LocalUser::ishighermodoradmincheck to enforc...