What is CVE-2025-6226?

CVE-2025-6226 is a medium-severity vulnerability in Mattermost, classified under Missing Authentication for Critical Function. CVSS score: 6.5/10. Published 2025-07-18.

How severe is CVE-2025-6226?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Auth bypass in Mattermost

CVE-2025-6226

Mattermost versions 10.5.x <= 10.5.6, 10.8.x <= 10.8.1, 10.7.x <= 10.7.3, 9.11.x <= 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the PendingPostID of recently created posts.

Vulnerability class: Broken Authentication

EPSS: 0.003 (23.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

Affected products

Mattermost — versions 10.5.0, 10.8.0, 10.7.0
Mattermost Mattermost_server

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

responsibledisclosure@mattermost.com (Vendor Advisory)

Frequently asked questions

What is CVE-2025-6226?: CVE-2025-6226 is a medium-severity vulnerability in Mattermost, classified under Missing Authentication for Critical Function. CVSS score: 6.5/10. Published 2025-07-18.
How severe is CVE-2025-6226?: Medium severity. CVSS v3 base score is 6.5 out of 10.