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
Published: 2026-09-17
Score: 2.6 Low
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

Vendor Solution

Update Mattermost Desktop App to versions 6.3.0, 6.2.3.0 or higher.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

References
Link Providers
https://mattermost.com/security-updates cve-icon cve-icon
History

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'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

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

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

Link: CVE-2026-75588

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

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

Modified: 2026-09-17T16:17:41.940

Link: CVE-2026-75588

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses