What is CVE-2025-12559?

CVE-2025-12559 is a medium-severity vulnerability in Mattermost, classified under Information Disclosure. CVSS score: 4.3/10. Published 2025-11-27.

How severe is CVE-2025-12559?

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

Information disclosure in Mattermost

CVE-2025-12559

Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to sanitize team email addresses to be visible only to Team Admins, which allows any authenticated user to view team email addresses via the GET /api/v4/channels/{channel_id}/common_teams endpoint

Vulnerability class: Information Disclosure

EPSS: 0.002 (11.3th 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 11.0.0, 10.12.0, 10.11.0
Mattermost Mattermost_server

Weakness classification (CWE)

CWE-200 — Information Disclosure

References

responsibledisclosure@mattermost.com (Vendor Advisory)

Frequently asked questions

What is CVE-2025-12559?: CVE-2025-12559 is a medium-severity vulnerability in Mattermost, classified under Information Disclosure. CVSS score: 4.3/10. Published 2025-11-27.
How severe is CVE-2025-12559?: Medium severity. CVSS v3 base score is 4.3 out of 10.