CVE-2026-4286 PUBLISHED

Playbooks Plugin fails to validate team transfers, allowing unauthorized removal of member access via playbook update

Assigner: Mattermost
Reserved: 16.03.2026 Published: 18.05.2026 Updated: 18.05.2026

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to check if {{team_id}} was being changed when updating playbooks, allowing users with only {{Manage Playbook Configurations}} permission to change a playbook's team, bypassing manage members restriction via PUT api. Mattermost Advisory ID: MMSA-2025-00552

Metrics

CVSS 3.1

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

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

CVSS 3.1

Product Status

Vendor	Mattermost
Product	Mattermost
Versions	Default: unaffected affected from 11.5.0 to 11.5.1 (incl.) affected from 10.11.0 to 10.11.13 (incl.) Version 11.6.0 is unaffected Version 11.5.2 is unaffected Version 10.11.14 is unaffected

Solutions

Update Mattermost to versions 11.6.0, 11.5.2, 10.11.14 or higher.

Credits

0x7oda7123 finder

References

MMSA-2025-00552

Problem Types

CWE-863: Incorrect Authorization CWE