---
id: CVE-2026-18256
title: Private team metadata disclosure via the team search API
summary: >-
  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 properly restrict private teams from public team
  search results, which allows an authenticated user without permission to list
  private t…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-863
vendor: Mattermost
product: Mattermost
affected:
  - Mattermost >= 11.10.0 <= 11.10.0
  - Mattermost >= 11.7.0 <= 11.7.9
  - Mattermost >= 11.9.0 <= 11.9.1
  - Mattermost >= 11.8.0 <= 11.8.5
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-16T11:57:52.562948Z'
published: '2026-10-16'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T11:58:08.912Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-18256'
references:
  - url: 'https://mattermost.com/security-updates'
    label: MMSA-2026-00748
tags:
  - cve.org
ingestedAt: '2026-10-16T08:02:23.121Z'
---

## Overview

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 properly restrict private teams from public team search results, which allows an authenticated user without permission to list private teams to disclose the ID, name, and display name of private teams via a modified team search request. Mattermost Advisory ID: MMSA-2026-00748

## Affected

- `Mattermost >= 11.10.0 <= 11.10.0`
- `Mattermost >= 11.7.0 <= 11.7.9`
- `Mattermost >= 11.9.0 <= 11.9.1`
- `Mattermost >= 11.8.0 <= 11.8.5`

## Remediation

Update Mattermost to versions 11.11.0, 11.10.1, 11.7.10, 11.9.2, 11.8.6 or higher.