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
AI Analysis

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Remediation

Vendor Solution

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

Tracking

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Advisories

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

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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

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses