CVE-2026-3471mediumCWE-939

CVE-2026-3471: medium-severity vulnerability in Mattermost

Opening a window with {{javascript:alert()}} as URL causes crash in the Mattermost Desktop App

Published

13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 6.5epss 0.3%
exploitation probability
0.3%top 76% of all CVEs
observed exploitation
nono source reports it
Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows a malicious server owner to repeated crash the application via calling {{window.open('javascript:alert()');}}. Mattermost Advisory ID: MMSA-2026-00618
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Affected products
Mattermost · Mattermost
Related CVEs — Mattermost

In the same product, most dangerous first.

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