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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

PUBLISHED Reserved 2026-03-16 | Published 2026-05-18 | Updated 2026-05-18 | Assigner Mattermost




MEDIUM: 4.3CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Problem types

CWE-863: Incorrect Authorization

Product status

Default status
unaffected

11.5.0 (semver)
affected

10.11.0 (semver)
affected

11.4.0 (semver)
affected

11.6.0
unaffected

11.5.2
unaffected

10.11.14
unaffected

11.4.4
unaffected

Credits

mr_anksec finder

References

mattermost.com/security-updates (MMSA-2026-00597) vendor-advisory

cve.org (CVE-2026-28732)

nvd.nist.gov (CVE-2026-28732)

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