CVE-2026-9812 — Missing property field ownership validation in Playbooks run property update endpoint

Description (CNA)

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 that a property field belongs to the specified run before updating its value which allows an authenticated user with run property-management access to crash the Playbooks plugin via a REST request referencing a property field that belongs to a different run. Mattermost Advisory ID: MMSA-2026-00684

Affected (CNA)

Vendor / product	Versions
Mattermost / Mattermost	affected 11.9.0 through 11.9.0; affected 11.8.0 through 11.8.4; affected 11.7.0 through 11.7.7; affected 10.11.0 through 10.11.22; unaffected 11.10.0; unaffected 11.9.1; unaffected 11.8.5; unaffected 11.7.8; unaffected 10.11.23

CWE

CWE-639

References

https://mattermost.com/security-updates

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.