Authorization Bypass Vulnerability in Mattermost by Mattermost
CVE-2026-27769

2.7LOW

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
15 April 2026

What is CVE-2026-27769?

The vulnerability in Mattermost versions 10.11.x up to 10.11.12 arises from a failure to properly validate user ownership within the Connected Workspaces feature. This oversight allows a malicious remote server, when connected through the Connected Workspaces API, to alter the displayed status of local users without proper authorization. This can lead to unauthorized access and manipulation of user information, posing serious security risks to the affected Mattermost installations.

Affected Version(s)

Mattermost 10.11.0 <= 10.11.12

Mattermost 11.5.0

Mattermost 10.11.13

References

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

CVSS V3.1

Score:
2.7
Severity:
LOW
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

daw10
.