Mend.io Vulnerability Database

What is a CVE vulnerability ID? icon What is a WS vulnerability ID? icon What is an MSC vulnerability ID? icon
New vulnerability? Tell us about it!
icon

We found results for “”

CVE-2026-21865

Good to know:

icon
icon

Date: 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.

Severity Score

Related Resources (3)

https://nvd.nist.gov/vuln/detail/CVE-2026-21865
https://github.com/discourse/discourse/security/advisories/GHSA-4777-wrv5-3g39
https://www.mend.io/vulnerability-database/CVE-2026-21865

Severity Score

Weakness Type (CWE)

Missing Authorization

CWE-862

Top Fix

icon

Upgrade Version

Upgrade to version https://github.com/discourse/discourse.git - v2026.1.0;https://github.com/discourse/discourse.git - v2025.11.2;https://github.com/discourse/discourse.git - v3.5.4;https://github.com/discourse/discourse.git - v2025.12.1

Learn More

CVSS v3.1

Base Score:
Attack Vector (AV): NETWORK
Attack Complexity (AC): LOW
Privileges Required (PR): HIGH
User Interaction (UI): NONE
Scope (S): UNCHANGED
Confidentiality (C): HIGH
Integrity (I): HIGH
Availability (A): NONE

Do you need more information?

Contact Us