CVE-2026-8823

Analyzed Analyzed - Analysis Complete

Bot Account Privilege Degradation in Mattermost

Publication date: 2026-06-22

Last updated on: 2026-06-26

Assigner: Mattermost, Inc.

Description

Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669

CVSS Scores

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Meta Information

Published

2026-06-22

Last Modified

2026-06-26

Generated

2026-07-13

AI Q&A

2026-06-22

EPSS Evaluated

2026-07-11

NVD

CVE-2026-8823

EUVD

EUVD-2026-38276

Affected Vendors & Products

Vendor	Product	Version / Range
mattermost	mattermost_server	From 10.11.0 (inc) to 10.11.18 (exc)
mattermost	mattermost_server	From 11.7.0 (inc) to 11.7.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-863	The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Attack-Flow Graph

Executive Summary

This vulnerability exists in Mattermost versions 11.7.x up to 11.7.0 and 10.11.x up to 10.11.17. It occurs because the software fails to properly validate bot targets when demoting users to guests. This flaw allows a lower-privileged administrator to degrade arbitrary bot accounts by using the standard demote-user API.

Impact Analysis

The impact of this vulnerability is that a lower-privileged administrator can reduce the privileges or degrade bot accounts that they should not have control over. This could lead to disruption of automated processes or integrations that rely on these bot accounts, potentially affecting the integrity and availability of services within the Mattermost environment.

Mitigation Strategies

To mitigate this vulnerability, you should update Mattermost to a version later than 11.7.0 or 10.11.17 where the issue has been fixed.

Monitor Mattermost security updates and advisories regularly to apply patches promptly.

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