PT-2026-7984 · Mattermost · Mattermost

Juho Forsén · Published 2026-02-13 · Updated 2026-03-03 · CVE-2026-20796

Positive Technologies (AI Summary)

CVSS v3.1

3.1

Low

Base vector

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

Name of the Vulnerable Software and Affected Versions Mattermost versions 10.11.0 through 10.11.9

Description Mattermost versions 10.11.0 through 10.11.9 do not properly validate channel membership when retrieving data, potentially allowing a deactivated user to learn team names they should not have access to. This occurs due to a race condition in the /common teams API endpoint.

Recommendations Update to a version later than 10.11.9.

Fix

Time Of Check To Time Of Use

Weakness Enumeration

CWE-367

Related Identifiers

CVE-2026-20796

GHSA-2XF7-HMF6-P64J

GO-2026-4495

SUSE-SU-2026:0757-1

Affected Products

Mattermost

References · 119

• https://nvd.nist.gov/vuln/detail/CVE-2026-20796 · Security Note
• https://mattermost.com/security-updates · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-20796 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-2xf7-hmf6-p64j · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2026:0757-1 · Vendor Advisory
• https://osv.dev/vulnerability/GO-2026-4495 · Vendor Advisory
• https://github.com/mattermost/mattermost · Note
• https://suse.com/security/cve/CVE-2017-18907 · Note
• https://suse.com/security/cve/CVE-2017-18916 · Note
• https://suse.com/security/cve/CVE-2026-25793 · Note
• https://suse.com/security/cve/CVE-2025-64641 · Note
• https://suse.com/security/cve/CVE-2026-23992 · Note
• https://suse.com/security/cve/CVE-2017-18915 · Note
• https://suse.com/support/update/announcement/2026/suse-su-20260757-1 · Note
• https://suse.com/security/cve/CVE-2026-27588 · Note