CVE-2026-3115

published 2026-03-26

CVE-2026-3115: Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs…

Priority P4 22 medium 4.3 CVSS 3.1

AV N AC L PR L UI N S U C L I N A N

Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594

Affected

13 ranges

Vendor	Product	Version range	Fixed in
github.com	mattermost_mattermost_server_v8	>= 10.11.0-rc1 < 10.11.11	10.11.11
github.com	mattermost_mattermost_server_v8	>= 11.2.0-rc1 < 11.2.3	11.2.3
github.com	mattermost_mattermost_server_v8	>= 11.3.0-rc1 < 11.3.2	11.3.2
github.com	mattermost_mattermost_server_v8	>= 11.4.0 < 11.4.1	11.4.1
github.com	mattermost_mattermost_server_v8	>= 8.0.0-20260105080200-d27a2195068d < 8.0.0-20260217110922-b7d4a1f1f59b	8.0.0-20260217110922-b7d4a1f1f59b
mattermost	mattermost	10.11.0 – 10.11.10	—
mattermost	mattermost	11.2.0 – 11.2.2	—
mattermost	mattermost	11.3.0 – 11.3.1	—
mattermost	mattermost	11.4.0 – 11.4.0	—
mattermost	mattermost_server	—	—
mattermost	mattermost_server	>= 10.11.0 < 10.11.11	10.11.11
mattermost	mattermost_server	>= 11.2.0 < 11.2.3	11.2.3
mattermost	mattermost_server	>= 11.3.0 < 11.3.2	11.3.2

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CWE-863