HIGHCVSS v3.1 8.6Vulnerability
CVE-2026-55103
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.
Properties
- Severity
- HIGH
- Nvd fetched at
- 2026-10-20T21:14:08.448323+00:00
- Epss score
- 0.002
- Cvss severity
- HIGH
- Cvss score
- 8.6
- Retrieved at
- 2026-10-21T01:24:49+00:00
- Last source
- FIRST EPSS
- Score
- 8.6
- Cvss version
- 3.1
- Cve id
- CVE-2026-55103
- Cvss vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
- First seen by Signal
- 2026-10-18T13:39:03+00:00
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
- Published at
- 2026-10-15T18:17:27.163
- Last modified
- 2026-10-16T20:04:29.760
- Epss percentile
- 0.09277
Related Entities (2)
HAS_WEAKNESS (2)
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