CVE-2026-28732: Slash command trigger-word update allowed command hijacking
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to enforce slash command trigger-word uniqueness during command updates which allows an authenticated team member with Manage Own Slash Commands permission to hijack and impersonate existing system or custom slash commands via editing their own slash command trigger to an already-registered trigger through the command update API. Mattermost Advisory ID: MMSA-2026-00597
Affected Software
Remediation
Information
Event History
Frequently Asked Questions
What is the severity of CVE-2026-28732?
CVE-2026-28732 is classified as a medium severity vulnerability due to its potential for command hijacking.
How do I fix CVE-2026-28732?
To fix CVE-2026-28732, update Mattermost to version 11.5.2 or later, 10.11.14 or later, or 11.4.4 or later.
What versions of Mattermost are affected by CVE-2026-28732?
CVE-2026-28732 affects Mattermost versions up to and including 11.5.1, 10.11.13, and 11.4.3.
What is the impact of CVE-2026-28732?
The impact of CVE-2026-28732 includes allowing authenticated users to hijack existing slash commands due to a lack of uniqueness enforcement.
Who is at risk for CVE-2026-28732?
Authenticated team members with Manage Own Slash Commands permission in the affected versions of Mattermost are at risk for CVE-2026-28732.