Vulnerability · Published May 18, 2026 · Assigned by Mattermost
CVE-2026-4286Playbooks Plugin fails to validate team transfers, allowing unauthorized removal of member access via playbook update
Low 3.1
In plain English
A low-severity incorrect authorization in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-plugin-playbooks | 1.41.1-0.20260213020129-e1d6ec2c94e6 | GHSA-gvg4-jhmr-6j23 |
| Go | github.com/mattermost/mattermost-plugin-playbooks | 1.41.1-0.20260213020129-e1d6ec2c94e6 | GO-2026-5404 |
| Go | github.com/mattermost/mattermost-server | 10.11.14+incompatible, 11.5.2+incompatible | GO-2026-5404 |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GO-2026-5404 |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GO-2026-5404 |
| Go | github.com/mattermost/mattermost/server/v8 | no fix listed | GO-2026-5404 |
| Go | github.com/mattermost/mattermost/server/v8 | 10.11.14 | GHSA-gvg4-jhmr-6j23 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.5.2 | GHSA-gvg4-jhmr-6j23 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 11.5.0 – through 11.5.110.11.0 – through 10.11.13 |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
References
- MMSA-2025-00552 vendor-advisory