CVE-2026-26230

LOW EPSS 5.5%

Published Mar 16, 20263mo ago · Modified Jun 17, 20261w ago

3.8 CVSS 3.1

Low

Published Mar 16, 2026 3mo ago

Last Modified Jun 17, 2026 1w ago

Description

Mattermost versions 10.11.x <= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531

CVSS Details

Base Score

3.8

Exploitability

1.2

Impact

2.5

Vector string

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

Attack Vector Network

Attack Complexity Low

Privileges Required High

User Interaction None

Scope Unchanged

Confidentiality Low

Integrity Low

Availability None

Threat Intelligence

EPSS Exploit Probability

5.5% percentile

Exploit & Patch Status

No Known Exploit

No Patch Available

Weaknesses 1

CWE-863 Incorrect Authorization Authorization

Affected Products 1

Vendor	Product	Version	Range
mattermost	mattermost_server	*	≥10.11.0 – <10.11.11

References 1

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

Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.