CVE-2026-21865

Discourse topic conversion permission vulnerability for moderators

State: Published
Severity: 6.5 Medium
Published: Jan 28, 2026
Updated: Jan 28, 2026
Reserved: Jan 5, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N	GitHub_M

Weaknesses

CWE-862 Missing Authorization

Affected Products

Product	Versions
discoursediscourse	< 3.5.4Affected >= 2025.11.0-latest, < 2025.11.2Affected >= 2025.12.0-latest, < 2025.12.1Affected >= 2026.1.0-latest, < 2026.1.0Affected

References

https://github.com/discourse/discourse/security/advisories/GHSA-4777-wrv5-3g39

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