CVE-2026-9708

published 2026-07-13

CVE-2026-9708: 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…

Priority P4 27 medium 4.9 CVSS 3.1

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

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

Affected

6 ranges

Vendor	Product	Version range	Fixed in
mattermost	mattermost	10.11.0 – 10.11.19	—
mattermost	mattermost	11.6.0 – 11.6.4	—
mattermost	mattermost	11.7.0 – 11.7.2	—
mattermost	mattermost_server	>= 10.11.0 < 10.11.20	10.11.20
mattermost	mattermost_server	>= 11.6.0 < 11.6.5	11.6.5
mattermost	mattermost_server	>= 11.7.0 < 11.7.3	11.7.3

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CWE-639