CVE-2026-28732 Details
Description
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
A vulnerability exists in Mattermost versions 11.5.x through 11.5.1, 10.11.x through 10.11.13, and 11.4.x through 11.4.3. These versions fail to enforce uniqueness of trigger words for slash commands during updates. This flaw allows an authenticated team member with the 'Manage Own Slash Commands' permission to hijack and impersonate existing system or custom slash commands. The vulnerability can be exploited by editing the trigger word of a user's own slash command to match that of an already registered command, using the command update API.
Users can upgrade to Mattermost versions 11.7.0, 11.6.1, or 10.11.16 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 18, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://mattermost.com/security-updates | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-863 | Incorrect Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| mattermost mattermost server | >= 10.11.0, < 10.11.14 >= 11.4.0, < 11.4.4 >= 11.5.0, < 11.5.2 |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 19, 2026 | Initial Analysis | [email protected] |
| May 18, 2026 | New CVE Received | [email protected] |