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VULNERABILITIES

CVE-2026-8821 Details

Description

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate channel member-management permission during playbook run creation, allowing an authenticated channel member to add an arbitrary user to a restricted channel via the run owner field.. Mattermost Advisory ID: MMSA-2026-00677

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:7.1 HIGHVector:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://mattermost.com/security-updates [email protected]

Weakness Enumeration

CWE-IDCWE NameSource
CWE-862Missing Authorization[email protected]

Affected Products

No affected product data is available for this CVE.

Change History

2 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-8821
NVD Published Date:
Sep 14, 2026
NVD Last Modified:
Sep 16, 2026
Source:
[email protected]
CVE-2026-8821 Details - Not Deferred