CVE-2025-55035

Mattermost Desktop App versions <=5.13.0 fail to manage modals in the Mattermost Desktop App that stops a user with a server that uses basic authentication from accessing their server which allows an attacker that provides a malicious server to the user to deny use of the Desktop App via having the user configure the malicious server and forcing a modal popup that cannot be closed.

Score

CVSS 3.1 6.1 Medium

Status

Analyzed - responsibledisclosure@mattermost.com

Published

2025-10-16

Last modified

2026-10-19

Weaknesses

CWE-754

Affected products

• Mattermost (Mattermost)
• Mattermost Desktop (Mattermost)

References

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