CVE-2026-8683

Overly long URLs crash the Mattermost Desktop App

CVSS 6.5 MEDIUMEPSS 0.2%CWE-770

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.5EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch referenciado

Lifecycle

15 Jun 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected products

Mattermost · Mattermost

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References

https://mattermost.com/security-updates