What is CVE-2026-3636?

CVE-2026-3636 is a medium-severity vulnerability in Mattermost, classified under Information Disclosure. CVSS score: 4.3/10. Published 2026-05-22.

How severe is CVE-2026-3636?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Information disclosure in Mattermost

CVE-2026-3636

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to sanitize team member data when returned via API to users without elevated permissions which allows a user without permissions to get data…

Vulnerability class: Information Disclosure

EPSS: 0.000 (7.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

Affected products

Mattermost — versions 11.6.0, 11.5.0, 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-2026-3636?: CVE-2026-3636 is a medium-severity vulnerability in Mattermost, classified under Information Disclosure. CVSS score: 4.3/10. Published 2026-05-22.
How severe is CVE-2026-3636?: Medium severity. CVSS v3 base score is 4.3 out of 10.