CVE-2025-55035 - CVE House

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Status published Medium CVE-2025-55035

Mattermost Desktop DoS when user has basic authentication server configured

6.1 CVSS

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

Doyensec

References

https://mattermost.com/security-updates

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Affected Vendor

Mattermost

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Affected Software

Mattermost

Vulnerable Versions:

0, 5.13.1.0

Timeline

Official Publish: October 16th, 2025

Last Modified: October 16th, 2025

Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:N/A:H

Weaknesses (CWE)

MITRE ATT&CK TTPs

T1190 Exploit Public-Facing Application

T1068 Exploitation for Privilege Escalation

Privilege Escalation

T1499 Endpoint Denial of Service

T1562 Impair Defenses

Defense Evasion

T1005 Data from Local System