PT-2020-8451 · Mattermost · Mattermost Server

Published 2020-06-19 · Updated 2026-01-17 · CVE-2017-18905

Positive Technologies (AI Summary)

CVSS v3.1

5.3

Medium

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Name of the Vulnerable Software and Affected Versions: Mattermost Server versions prior to 4.0.0 Mattermost Server version 3.10.2 Mattermost Server version 3.9.2

Description: An issue was discovered in Mattermost Server when used as an OAuth 2.0 service provider, where session invalidation was mishandled.

Recommendations: For versions prior to 4.0.0, update to version 4.0.0 or later. For version 3.10.2, update to version 4.0.0 or later. For version 3.9.2, update to version 4.0.0 or later.

Fix

Insufficient Session Expiration

Weakness Enumeration

CWE-613

Related Identifiers

CVE-2017-18905

GHSA-G24C-FX4V-XG9W

GO-2026-4306

SUSE-SU-2026:0142-1

Affected Products

Mattermost Server

References · 45

• https://osv.dev/vulnerability/CVE-2017-18905 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-g24c-fx4v-xg9w · Vendor Advisory
• https://osv.dev/vulnerability/GO-2026-4306 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2017-18905 · Security Note
• https://osv.dev/vulnerability/SUSE-SU-2026:0142-1 · Vendor Advisory
• https://mattermost.com/security-updates · Vendor Advisory
• https://github.com/mattermost/mattermost · Note
• https://github.com/mattermost/mattermost/commit/15ad24d160cb4604d0605ebbfa53d11a57820706 · Note
• https://github.com/mattermost/mattermost/commit/fbc170733e86f09b46ba754dd03304733d2f482f · Note
• https://github.com/mattermost/mattermost/commit/b17fca0d5ee7557e3df1cf1d1da8bd749859e35f · Note
• https://suse.com/security/cve/CVE-2026-22688 · Note
• https://suse.com/security/cve/CVE-2026-21859 · Note
• https://suse.com/support/update/announcement/2026/suse-su-20260142-1 · Note
• https://suse.com/security/cve/CVE-2026-22703 · Note
• https://suse.com/security/cve/CVE-2025-68954 · Note