CVE-2026-58593: exploitation status and patch state
CVE-2026-58593 · CVSS 7.5 HIGH · EPSS <1%
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, attributedTo is used directly as a uid, and actors.assert silently ignores numeric identifiers (filtering them out without re-deriving the uid), so a federated remote actor can set attributedTo to a bare numeric value such as 1 and have the resulting post or private message created with that local uid as author, including the administrator account. This lets a remote attacker forge posts and direct messages attributed to arbitrary local users. Requires the ActivityPub/federation feature to be enabled.
Is CVE-2026-58593 exploited?
Not in the CISA KEV catalog.
EPSS puts exploitation in the next 30 days at <1%.
Public exploit code: none found in monitored sources.