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 Details

CVSS 3.1 Base Score: 6.5
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)

Prioritise with Active Threat Intelligence

With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.

Explore Intelligence Hub

MDR Buyer's Guide

Global Threat Landscape Report

Grow your business

CVSS Details

Prioritise with Active Threat Intelligence

MDR Buyer's Guide

Global Threat Landscape Report

Grow your business

CVE-2026-3471: Improper Authorization in Handler for Custom URL Scheme

CVSS Details

Prioritise with Active Threat Intelligence