CVE-2026-9812 PUBLISHED

Missing property field ownership validation in Playbooks run property update endpoint

Assigner: Mattermost
Reserved: 28.05.2026 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 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

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 6.5

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

  • alimursaliyev finder

References

Problem Types

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