Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate that an assigned incoming webhook user has access to the target team or channel, which allows a requester with webhook management permissions to create posts or direct messages attributed to another user via crafted incoming webhook configuration and payloads.. Mattermost Advisory ID: MMSA-2026-00683
CVSS Details
- CVSS 3.1 Base Score: 4.9
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N)
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