What is CVE-2026-3108?

CVE-2026-3108 is a high-severity vulnerability in Mattermost, classified under CWE-150. CVSS score: 8.0/10. Published 2026-03-26.

How severe is CVE-2026-3108?

High severity. CVSS v3 base score is 8.0 out of 10.

Vulnerability in Mattermost

CVE-2026-3108

Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to sanitize user-controlled post content in the mmctl commands terminal output which allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences that enable screen manipulation, fake prompts, and clipboard hijacking.. Mattermost Advisory ID: MMSA-2026-00599

Published 2026-03-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.0 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (25.3th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.001

Affected products

Mattermost — versions 11.2.0, 10.11.0, 11.4.0
Mattermost Server — versions 11.4.0

Weakness classification (CWE)

CWE-150

References

mattermost.com/security-updates (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-3108?: CVE-2026-3108 is a high-severity vulnerability in Mattermost, classified under CWE-150. CVSS score: 8.0/10. Published 2026-03-26.
How severe is CVE-2026-3108?: High severity. CVSS v3 base score is 8.0 out of 10.