CVE-2026-16046

Medium

Description

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to enforce run-state validation on write operations for finished playbook runs which allows a run participant to modify status, checklists, retrospective content, ownership, and participants on completed runs via REST and GraphQL API requests. Mattermost Advisory ID: MMSA-2026-00675

SeverityMedium

CVSS4.3

Exploit probability—

Product

Mattermost Server

PublishedAug 17, 2026

First seenAug 17, 2026

Weakness typeCWE-863Incorrect authorization

How to fix

Update

mattermost mattermost_server10.11.22, 11.7.7 or later

Vendor advisories

mattermost.com/security-updates

Affected products

Product	Affected versions	Fixed in
mattermost mattermost_server	10.11.0 ≤ v < 10.11.22, 11.7.0 ≤ v < 11.7.7	10.11.22, 11.7.7

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