CVE-2026-10085

Ordinary group/direct message member can enable group_constrained and remove all channel participants

State: Published
Severity: 5.4 Medium
Published: Jul 13, 2026
Updated: Jul 13, 2026
Reserved: May 29, 2026

Description

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained channel flag to public and private channels that support group synchronization, which allows an ordinary group or direct message member to remove all participants from the conversation via the channel patch API.. Mattermost Advisory ID: MMSA-2026-00688

Scores

CVSS	Score	Vector	Source
3.1	5.4 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L	Mattermost

Weaknesses

CWE-862 Missing Authorization

Affected Products

Product	Versions
MattermostMattermost	11.7.0 through 11.7.2Affected 11.6.0 through 11.6.4Affected 10.11.0 through 10.11.19Affected 11.8.0Not affected 11.7.3Not affected 11.6.5Not affected 10.11.20Not affected

References

MMSA-2026-00688vendor-advisory

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