CVE-2026-21865
January 28, 2026
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 Packages
https://github.com/discourse/discourse.git (GITHUB):
Affected version(s) >=v2025.11.0 <v2025.11.2Fix Suggestion:
Update to version v2025.11.2https://github.com/discourse/discourse.git (GITHUB):
Affected version(s) >=v0.8.0 <v3.5.4Fix Suggestion:
Update to version v3.5.4https://github.com/discourse/discourse.git (GITHUB):
Affected version(s) >=v2026.1.0 <v2026.1.0Fix Suggestion:
Update to version v2026.1.0Related Resources (1)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.5
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
HIGH
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Missing Authorization
EPSS
Base Score:
0.04
