Vulnerability in Mattermost

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.003 (22.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 22.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-55035: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-55035?
CVE-2025-55035 is a medium-severity vulnerability in Mattermost, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 6.1/10. Published 2025-10-16.
How severe is CVE-2025-55035?
Medium severity. CVSS v3 base score is 6.1 out of 10.