CVE-2026-18795 - Vulnerability Details - OpenCVE

Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact Low

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact partial

Vendors	Products
Mattermost	Mattermost

No data.

No data.

References

Link	Providers
https://mattermost.com/security-updates

History

Sat, 17 Oct 2026 16:45:00 +0000

Type	Values Removed	Values Added
First Time appeared		Mattermost Mattermost mattermost
Vendors & Products		Mattermost Mattermost mattermost

Fri, 16 Oct 2026 13:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Fri, 16 Oct 2026 07:15:00 +0000

Type	Values Removed	Values Added
Description		Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756
Title		Missing server side validation allowed user to quarantine a DM and GM post
Weaknesses		CWE-862
References		https://mattermost.com/security-updates
Metrics		cvssV3_1 `{'score': 6.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L'}`

MITRE

Status: PUBLISHED

Assigner: Mattermost

Published: 2026-10-16T07:01:22.549Z

Updated: 2026-10-16T11:59:42.771Z

Reserved: 2026-08-04T09:13:11.334Z

Link: CVE-2026-18795

Vulnrichment

Updated: 2026-10-16T11:59:37.292Z

NVD

Status : Awaiting Analysis

Published: 2026-10-16T07:17:12.407

Modified: 2026-10-16T19:23:18.623

Link: CVE-2026-18795

Redhat

No data.

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