CVE-2026-2458CWE-862

Unauthorized channel enumeration in private teams after member removal

Medium · published March 16, 2026

CVSS v3.1
4.3
EPSS
0%
Percentile
5.8
In the wild
Unconfirmed
What it is

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

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00168 · 5.8th percentile
Weakness
CWE-862 · Missing Authorization
Published
2026-03-16T11:27Z
EPSS history
Timeline
  • 16 MAR 11:27Z
    Unauthorized channel enumeration in private teams after member removal
    cvelistv5