Vulnerability in Mattermost
CVE-2026-9597
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4 fail to verify whether a guest account is deactivated before creating a session in the magic-link token login path, which allows a deactivated guest user to obtain a fully functional s…
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.
Affected products
- Mattermost — versions 11.7.0, 11.6.0, 11.8.0
- Mattermost Mattermost_server
Weakness classification (CWE)
References
- responsibledisclosure@mattermost.com (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-9597?
- CVE-2026-9597 is a medium-severity vulnerability in Mattermost, classified under Authentication Bypass by Primary Weakness. CVSS score: 5.4/10. Published 2026-07-13.
- How severe is CVE-2026-9597?
- Medium severity. CVSS v3 base score is 5.4 out of 10.