What is CVE-2025-27715?

CVE-2025-27715 is a low-severity vulnerability in Mattermost, classified under Incorrect Authorization. CVSS score: 3.3/10. Published 2025-03-21.

How severe is CVE-2025-27715?

Low severity. CVSS v3 base score is 3.3 out of 10.

Auth bypass in Mattermost

CVE-2025-27715

Mattermost versions 9.11.x <= 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel, which team admins to joining private channels via crafted permalink links without explicit consent from them.

Vulnerability class: Broken Access Control

Published 2025-03-21 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (10.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Mattermost — versions 9.11.0, 10.5.0, 9.11.9
Mattermost Server

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

mattermost.com/security-updates (Vendor Advisory)

Frequently asked questions

What is CVE-2025-27715?: CVE-2025-27715 is a low-severity vulnerability in Mattermost, classified under Incorrect Authorization. CVSS score: 3.3/10. Published 2025-03-21.
How severe is CVE-2025-27715?: Low severity. CVSS v3 base score is 3.3 out of 10.