CVE-2026-2458mediumCWE-862

CVE-2026-2458: medium-severity vulnerability in Mattermost

Unauthorized channel enumeration in private teams after member removal

Published

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 4.3epss 0.2%
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
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Affected products
Mattermost · Mattermost
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