Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to use consistent error responses when handling the /mute command which allows an authenticated team member to enumerate private channels they are not authorized to know about via differing error messages for nonexistent versus private channels. Mattermost Advisory ID: MMSA-2026-00588
Metrics
Affected Vendors & Products
References
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| https://mattermost.com/security-updates |
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History
Tue, 17 Mar 2026 10:00:00 +0000
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Mon, 16 Mar 2026 19:15:00 +0000
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ssvc
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Mon, 16 Mar 2026 15:15:00 +0000
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| Description | Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to use consistent error responses when handling the /mute command which allows an authenticated team member to enumerate private channels they are not authorized to know about via differing error messages for nonexistent versus private channels. Mattermost Advisory ID: MMSA-2026-00588 | |
| Title | Private channel enumeration via /mute slash command | |
| Weaknesses | CWE-203 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: Mattermost
Published: 2026-03-16T14:51:43.263Z
Updated: 2026-03-16T18:39:14.064Z
Reserved: 2026-02-13T10:01:31.918Z
Link: CVE-2026-21386
Updated: 2026-03-16T18:39:06.523Z
Status : Awaiting Analysis
Published: 2026-03-16T15:16:20.927
Modified: 2026-03-17T14:20:01.670
Link: CVE-2026-21386
No data.