CVE-2026-3471

MEDIUM

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

Title source: cna
STIX 2.1

Description

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00618
https://mattermost.com/security-updates

Scores

CVSS v3 6.5
EPSS 0.0004
EPSS Percentile 11.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-939
Status published
Products (5)
Mattermost/Mattermost < 5.4.13
Mattermost/Mattermost < 6.0.1
Mattermost/Mattermost 5.13.5.0
Mattermost/Mattermost 6.1.1.0
Mattermost/Mattermost 6.2.0
Published May 18, 2026
Tracked Since May 18, 2026