CVE-2026-9602

Mattermost Desktop App versions <=6.2 6.0.2 5.6.13.0 fail to validate payloads sent from the Mattermost Web App to the Desktop App which allows a malicious server owner to crash the Mattermost Desktop App via changing the payload of a method to a malformed one. Mattermost Advisory ID: MMSA-2026-00678

Score

CVSS 3.1 6.5 Medium

Status

Analyzed - responsibledisclosure@mattermost.com

Published

2026-07-17

Last modified

2026-10-15

Weaknesses

CWE-400

Affected products

• Mattermost (Mattermost)
• Mattermost Desktop (Mattermost)

References

• https://mattermost.com/security-updates