CVE-2026-15754mediumCWE-863

CVE-2026-15754: medium-severity vulnerability in Mattermost

Missing per-channel team-scope check in ABAC access control policy unassign allows cross-team policy removal

Published

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 4.2epss 0.2%
Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy assignments from channels outside their team via the policy unassign API after a channel has been moved to another team.. Mattermost Advisory ID: MMSA-2026-00718
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:H/A:N
Affected products
Mattermost · Mattermost
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