CVE-2026-58593

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.
Configurations

Configuration 1 (hide)

cpe:2.3:a:nodebb:nodebb:*:*:*:*:*:*:*:*

History

02 Jul 2026, 19:42

Type Values Removed Values Added
References () https://github.com/NodeBB/NodeBB/blob/v4.13.2/src/activitypub/mocks.js - () https://github.com/NodeBB/NodeBB/blob/v4.13.2/src/activitypub/mocks.js - Exploit, Third Party Advisory
References () https://github.com/bikini/exploitarium/tree/main/nodebb-activitypub-attributedto-local-uid-spoof-poc - () https://github.com/bikini/exploitarium/tree/main/nodebb-activitypub-attributedto-local-uid-spoof-poc - Exploit, Third Party Advisory
References () https://www.vulncheck.com/advisories/nodebb-activitypub-author-spoofing-via-unvalidated-attributedto-mapped-to-local-user - () https://www.vulncheck.com/advisories/nodebb-activitypub-author-spoofing-via-unvalidated-attributedto-mapped-to-local-user - Exploit, Third Party Advisory
CPE cpe:2.3:a:nodebb:nodebb:*:*:*:*:*:*:*:*
First Time Nodebb nodebb
Nodebb

01 Jul 2026, 20:17

Type Values Removed Values Added
New CVE

Information

Published : 2026-07-01 20:17

Updated : 2026-07-07 13:16


NVD link : CVE-2026-58593

Mitre link : CVE-2026-58593

CVE.ORG link : CVE-2026-58593


JSON object : View

Products Affected

nodebb

  • nodebb
CWE
CWE-290

Authentication Bypass by Spoofing

CWE-345

Insufficient Verification of Data Authenticity