Vulnerability · Published Oct 16, 2025 · Assigned by Mattermost

CVE-2025-55035Mattermost Desktop DoS when user has basic authentication server configured

Medium 6.1

In plain English

A medium-severity security flaw in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities).

Severity (CVSS 3.1)6.1Medium
Exploit odds (30 days)0.3%top 75.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
Mattermost Mattermost 0 – through 5.0.13

Weakness: CWE-754 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:N/A:H

References