Mattermost Desktop App versions <=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717
References
History

Tue, 13 Oct 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost mattermost Desktop
CPEs cpe:2.3:a:mattermost:mattermost_desktop:*:*:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Desktop

Thu, 17 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Metrics ssvc

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


Thu, 17 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Description Mattermost Desktop App versions <=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717
Title Mattermost Desktop App plugin popout scheme validation bypass
Weaknesses CWE-1287
References
Metrics cvssV3_1

{'score': 2.6, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published: 2026-09-17T15:09:40.829Z

Updated: 2026-09-17T19:22:50.101Z

Reserved: 2026-08-17T22:19:32.227Z

Link: CVE-2026-75588

cve-icon Vulnrichment

Updated: 2026-09-17T19:22:40.335Z

cve-icon NVD

Status : Analyzed

Published: 2026-09-17T16:17:41.940

Modified: 2026-10-13T12:02:58.587

Link: CVE-2026-75588

cve-icon Redhat

No data.