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CVE-2026-55103

8.6 high SSVC exploitation: none Deferred
NVD · CVE.org

Discourse ActivityPub adds ActivityPub support to Discourse. Prior to commit 1c8518b0f2abdf31cbea3e0b242f74d8994a9ba5, inbound ActivityPub processing does not sufficiently verify that the actor authenticated by the signed request matches the Activity actor and owns the referenced federated post. A remote attacker can exploit these missing identity and ownership checks to edit, delete, or reply to federated posts without the required permissions. This vulnerability is fixed with commit 1c8518b0f2abdf31cbea3e0b242f74d8994a9ba5.

Fix

Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.

Change history 2

  1. StatusReceived → DeferredNVD modified 2026-10-16 20:04
  2. First seenCVSS 8.6NVD modified 2026-10-15 18:17

Affected (CPE criteria) 0

NVD has not attached CPE configurations yet.

References 2