CVEvulnerability

CVE-2026-18551

6.5 MEDIUM Published 2026-10-16 Modified 2026-10-29 Official page ↗
Status
Analyzed
Published
2026-10-16
Last modified
2026-10-29
Assigner
[email protected]
CVSS 3.1 ([email protected])
6.5 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Weaknesses
CWE-863

Description

Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to validate the combination of guest and admin scheme roles which allows an authenticated attacker to escalate a guest account to team or channel admin via a crafted PUT request to the member roles API endpoint.. Mattermost Advisory ID: MMSA-2026-00752

Affected configurations

• mattermost mattermost server (>= 11.7.0 < 11.7.10) • mattermost mattermost server (>= 11.8.0 < 11.8.6) • mattermost mattermost server (>= 11.9.0 < 11.9.2) • mattermost mattermost server 11.10.0

Related

Weakness · CWE (1)

  • CWE-863 Incorrect Authorization weakness

References