What is CVE-2025-27933?

CVE-2025-27933 is a medium-severity vulnerability in Mattermost, classified under Incorrect Authorization. CVSS score: 5.4/10. Published 2025-03-21.

How severe is CVE-2025-27933?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Auth bypass in Mattermost

CVE-2025-27933

Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to fail to enforce channel conversion restrictions, which allows members with permission to convert public channels to private ones to also convert private ones to public

Vulnerability class: Broken Access Control

EPSS: 0.002 (9.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.

Affected products

Mattermost — versions 10.4.0, 10.3.0, 9.11.0
Mattermost Mattermost_server

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

responsibledisclosure@mattermost.com (Vendor Advisory)

Frequently asked questions

What is CVE-2025-27933?: CVE-2025-27933 is a medium-severity vulnerability in Mattermost, classified under Incorrect Authorization. CVSS score: 5.4/10. Published 2025-03-21.
How severe is CVE-2025-27933?: Medium severity. CVSS v3 base score is 5.4 out of 10.