What is CVE-2026-6346?

CVE-2026-6346 is a high-severity vulnerability in Mattermost, classified under Information Disclosure. CVSS score: 8.7/10. Published 2026-05-18.

How severe is CVE-2026-6346?

High severity. CVSS v3 base score is 8.7 out of 10.

Information disclosure in Mattermost

CVE-2026-6346

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to sanitize sensitive configuration fields before including them in support packet generation, which allows a Mattermost System Admin or any party with access…

Vulnerability class: Information Disclosure

EPSS: 0.000 (12.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N.

Affected products

Mattermost — versions 11.5.0, 10.11.0, 11.4.0
Mattermost Mattermost_server

Weakness classification (CWE)

CWE-200 — Information Disclosure

References

responsibledisclosure@mattermost.com (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-6346?: CVE-2026-6346 is a high-severity vulnerability in Mattermost, classified under Information Disclosure. CVSS score: 8.7/10. Published 2026-05-18.
How severe is CVE-2026-6346?: High severity. CVSS v3 base score is 8.7 out of 10.