CVE-2026-20796

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-20796
Mattermost versions 10.11.x <= 10.11.9 fail to properly validate channel membership at the time of data retrieval which allows a deactivated user to learn team names they should not have access to via a race condition in the /common_teams API endpoint.. Mattermost Advisory ID: MMSA-2025-00549

3.1 /10

CVSS v3 : LOW

V3 Legend

Vector :

Exploitability : 1.6 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References
Link Resource
https://mattermost.com/security-updates Vendor Advisory
Configurations

Configuration 1 (hide)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
History

23 Feb 2026, 15:53

Type Values Removed Values Added
References () https://mattermost.com/security-updates - () https://mattermost.com/security-updates - Vendor Advisory
Summary
  • (es) Las versiones de Mattermost 10.11.x &lt;= 10.11.9 no validan correctamente la membresía del canal en el momento de la recuperación de datos, lo que permite a un usuario desactivado conocer nombres de equipos a los que no debería tener acceso a través de una condición de carrera en el endpoint de la API /common_teams. ID de Aviso de Mattermost: MMSA-2025-00549
CPE cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
First Time Mattermost
Mattermost mattermost Server

13 Feb 2026, 11:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-02-13 11:16

Updated : 2026-02-23 15:53

NVD link : CVE-2026-20796

Mitre link : CVE-2026-20796

CVE.ORG link : CVE-2026-20796

JSON object : View

Products Affected

mattermost

  • mattermost_server
CWE
CWE-367

Time-of-check Time-of-use (TOCTOU) Race Condition