CVE-2026-1046

Arbitrary application execution via unvalidated server-controlled URLs in Help menu

State: Published
Severity: 7.6 High
Published: Feb 16, 2026
Updated: Feb 17, 2026
Reserved: Jan 16, 2026

Description

Mattermost Desktop App versions <=6.0 6.2.0 5.2.13.0 fail to validate help links which allows a malicious Mattermost server to execute arbitrary executables on a user’s system via the user clicking on certain items in the Help menu Mattermost Advisory ID: MMSA-2026-00577

Scores

CVSS	Score	Vector	Source
3.1	7.6 High	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:L	Mattermost

Weaknesses

CWE-939 Improper Authorization in Handler for Custom URL Scheme

Affected Products

Product	Versions
MattermostMattermost	6.2.0 and earlierAffected 5.2.13 and earlierAffected 6.1.0Not affected 6.0.3.0Not affected 5.13.3.0Not affected

References

MMSA-2026-00577vendor-advisory

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