CVE-2026-58593 NodeBB - ActivityPub Author Spoofing via Unvalidated attributedTo Mapped to Local User

NodeBB does not bind the claimed author of an inbound ActivityPub object to the authenticated remote actor. The inbound middleware verifies the HTTP-signature actor and checks the origin of object.id, but never validates that attributedTo corresponds to the sender. In the object mock, attributedT...