CVE-2026-2458 MEDIUM

CVE-2026-2458: Unauthorized channel enumeration in private teams after member removal

Vendor Mattermost
Product Mattermost
Weakness CWE-862 · Missing authorization
Published March 16, 2026
Last update March 16, 2026
View on NVD All CVEs

CVSS base score

4.3/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality Low
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

What the vulnerability does

01Description

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID: MMSA-2025-00568

Key dates

02Disclosure timeline

March 16, 2026 CVE published
March 16, 2026 Record updated