CVE-2026-54742

In Lemmy versions 0.19.18 through 0.19.19 and 1.0.0-alpha.20, the CollectionAdd::Featured and CollectionRemove handlers in crates/apub/activities/src/community/collection_add.rs and collection_remove.rs dereference self.object as an ApubPost and update featured_community without verifying post.co...