CVE-2025-55035

low-risk

Published 2025-10-16

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.

Do I need to act?

0.04% chance of exploitation

EPSS score — low exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 6.1/10 Medium

NETWORK / HIGH complexity

Affected Products (1)

Mattermost Desktop

Affected Vendors

Mattermost

References (1)

Vendor Advisory https://mattermost.com/security-updates

/ 100

low-risk

Severity 19/34 · Moderate

Exploitability 0/34 · Minimal

Exposure 5/34 · Minimal