medium6.5
CVE-2026-21865
Discourse is an open source discussion platform.
Impact
Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, moderators can convert some personal messages to public topics when they shouldn't have access. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. As a workaround, site admin can temporarily revoke the moderation role from untrusted moderators or remove the moderator group from the "personal message enabled groups" site setting until the Discourse instance has been upgraded to a version that has been patched.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Discourse | Discourse | before 3.5.4 from 2025.11.0 before 2025.11.2 Versions 2025.12.0, 2026.1.0 |