Remote Code Execution Vulnerability in Mattermost Desktop App
CVE-2026-12284

3.8LOW

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
17 September 2026

What is CVE-2026-12284?

The Mattermost Desktop App contains a vulnerability that fails to properly validate the Inter-Process Communication (IPC) sender in its leaveCall handler. This shortcoming allows an attacker using a malicious or compromised Mattermost server, or a user with unauthorized script access to a connected server, to disconnect an active call associated with another server through the desktopAPI.leaveCall IPC message. Such a flaw poses significant risks to the integrity of ongoing communications within the app, leading to potential disruptions and exploitation of the communication capabilities.

Affected Version(s)

Mattermost 0 <= 6.2.2

Mattermost 6.3.0

Mattermost 6.2.3.0

References

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

CVSS V3.1

Score:
3.8
Severity:
LOW
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Juho Forsén
.