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Medium 4.3Published May 18, 2026

CVE-2026-28732Mattermost 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…

Updated under an hour ago ()

Does this affect you?

It affects mattermost_server. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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

CVSS
4.3 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE)
CWE-863
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Not given
NVD analysis
Analyzed
Record last updated
Oct 14, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
mattermost mattermost_server
mattermost:mattermost_server
from 10.11.0 before 10.11.14; from 11.4.0 before 11.4.4; from 11.5.0 before 11.5.2
NVD

References

  • vendor-advisory

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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