CVE-2026-8683

Mattermost Desktop App versions <=6.1 5.5.13.0 fail to account for attempting to open extremely long URLs in the Mattermost Desktop App which allows a malicious server owner to crash the application via including a script to call window.open on a very large URL. Mattermost Advisory ID: MMSA-2026-00652

Score

CVSS 3.1 6.5 Medium

Status

Analyzed - responsibledisclosure@mattermost.com

Published

2026-06-15

Last modified

2026-06-15

Weaknesses

CWE-770

Affected products

• Mattermost (Mattermost)
• Mattermost Desktop (Mattermost)

References

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