CVE-2026-96259

published 2026-09-22

CVE-2026-96259: Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint…

Priority P4 29 medium 5.5 CVSS 3.1

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

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776

Affected

8 ranges

Vendor	Product	Version range	Fixed in
mattermost	mattermost	11.10.0 – 11.10.1	—
mattermost	mattermost	11.7.0 – 11.7.10	—
mattermost	mattermost	11.8.0 – 11.8.5	—
mattermost	mattermost	11.9.0 – 11.9.1	—
mattermost	mattermost_server	>= 11.10.0 < 11.10.2	11.10.2
mattermost	mattermost_server	>= 11.7.0 < 11.7.11	11.7.11
mattermost	mattermost_server	>= 11.8.0 < 11.8.6	11.8.6
mattermost	mattermost_server	>= 11.9.0 < 11.9.2	11.9.2

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CWE-918