CVE-2026-2458

MEDIUM

Unauthorized channel enumeration in private teams after member removal

Title source: cna
STIX 2.1

Description

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2025-00568
https://mattermost.com/security-updates

Scores

CVSS v3 4.3
EPSS 0.0004
EPSS Percentile 12.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-862
Status published
Products (10)
mattermost/mattermost 0 - 8.0.0-20260113182106-a18b80ba4c32Go
Mattermost/Mattermost 10.11.0 - 10.11.10
Mattermost/Mattermost 10.11.11
Mattermost/Mattermost 11.2.0 - 11.2.2
Mattermost/Mattermost 11.2.3
Mattermost/Mattermost 11.3.0
Mattermost/Mattermost 11.3.1
Mattermost/Mattermost 11.4.0
mattermost/mattermost-server 0 - 5.3.2-0.20260113182106-a18b80ba4c32Go
mattermost/mattermost_server 10.11.0 - 10.11.11
Published Mar 16, 2026
Tracked Since Mar 16, 2026