CVE-2026-8683

Overly long URLs crash the Mattermost Desktop App

Published Jun 15, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
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

Remediation

Vendor Solution

Update Mattermost Desktop App to versions 6.2.0, 5.13.6.0 or higher.

Tracking

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Advisories

No advisories available
References
History
Type Values Removed Values Added
First Time appeared Mattermost mattermost Desktop
CPEs cpe:2.3:a:mattermost:mattermost_desktop:*:*:*:*:*:*:*:*
cpe:2.3:a:mattermost:mattermost_desktop:*:-:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Desktop
Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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
Title Overly long URLs crash the Mattermost Desktop App
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Jun 15, 2026, 4:06 PM
Reserved
May 15, 2026, 2:13 PM
Status
Analyzed
Published
Jun 15, 2026, 4:16 PM
Modified
Jun 17, 2026, 11:04 AM