CVE-2026-10542 PUBLISHED

Playbooks channel action update validation issue

Assigner: Mattermost
Reserved: 01.06.2026 Published: 14.09.2026 Updated: 14.09.2026

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate channel action ownership which allows channel managers to update actions in other channels via the channel action update endpoint.. Mattermost Advisory ID: MMSA-2026-00692

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
CVSS Score: 5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	Low
Privileges Required	Low	Integrity Impact	Low
User Interaction	None	Availability Impact	Low

CVSS 3.1

Product Status

Vendor	Mattermost
Product	Mattermost
Versions	Default: unaffected affected from 11.9.0 to 11.9.0 (incl.) affected from 11.8.0 to 11.8.4 (incl.) affected from 11.7.0 to 11.7.7 (incl.) affected from 10.11.0 to 10.11.22 (incl.) Version 11.10.0 is unaffected Version 11.9.1 is unaffected Version 11.8.5 is unaffected Version 11.7.8 is unaffected Version 10.11.23 is unaffected

Solutions

Update Mattermost to versions 11.10.0, 11.9.1, 11.8.5, 11.7.8, 10.11.23 or higher.

Credits

minghseinyuc86595 finder

References

MMSA-2026-00692

Problem Types

CWE-639: Authorization Bypass Through User-Controlled Key CWE