Access Control Bypass in Mattermost Playbook Configuration
CVE-2026-4286

3.1LOW

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
18 May 2026

What is CVE-2026-4286?

Mattermost versions 11.5.x up to 11.5.1 and 10.11.x up to 10.11.13 contain a vulnerability that allows users with only the Manage Playbook Configurations permission to alter a playbook's associated team ID. This occurs during updates, enabling unauthorized changes that circumvent member management restrictions through the PUT API. This issue potentially compromises the intended security posture of playbook management.

Affected Version(s)

Mattermost 11.5.0 <= 11.5.1

Mattermost 10.11.0 <= 10.11.13

Mattermost 11.6.0

References

https://mattermost.com/security-updates
vendor-advisory

CVSS V3.1

Score:
3.1
Severity:
LOW
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

0x7oda7123
.