CVE-2025-10545

Guest user can add unauthorized team users to private channels

State: Published
Severity: 3.1 Low
Published: Oct 16, 2025
Updated: Oct 16, 2025
Reserved: Sep 16, 2025

Description

Mattermost versions 10.5.x <= 10.5.10, 10.11.x <= 10.11.2 fail to properly validate guest user permissions when adding channel members which allows guest users to add any team members to their private channels via the `/api/v4/channels/{channel_id}/members` endpoint

Scores

CVSS	Score	Vector	Source
3.1	3.1 Low	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N	Mattermost

Weaknesses

CWE-863 Incorrect Authorization

Affected Products

Product	Versions
MattermostMattermost	10.5.0 through 10.5.10Affected 10.11.0 through 10.11.2Affected 10.12.0Not affected 10.5.11Not affected 10.11.3Not affected

References

https://mattermost.com/security-updates

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