# CVE-2026-28732: Slash command trigger-word update allowed command hijacking

> CVE-2026-28732: Slash command trigger-word update allowed command hijacking. CVSS 4.3 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-28732
Last updated: 2026-10-14T20:10:00Z

- Published: 2026-05-18 08:35 UTC · Updated: 2026-10-14 20:10 UTC · Assigner: Mattermost
- CVSS: 4.3 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- EPSS: 0.15%, 4th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-863

## 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

## Affected vendors and products

- Mattermost: Mattermost

## Tracked companies

- [Mattermost](https://rewindex.com/company/mattermost.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-28732)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-28732)
- [https://mattermost.com/security-updates](https://mattermost.com/security-updates)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-28732 · Markdown: https://rewindex.com/cve/CVE-2026-28732.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-28732 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:11:33.065Z