CVE-2026-9820

Mattermost schemes teams endpoint exposes private team invite IDs

Published Jul 13, 2026 CVSS 3.1 · 3.8 Low EPSS < 1% KEV · Not listed
Description
Mattermost versions 11.7.x <= 11.7.2, 10.11.x <= 10.11.19 fail to sanitize team objects returned by the scheme teams endpoint, which allows a user with the User Manager role to obtain invite links for private teams and use them to join or share access to those teams via the scheme teams API endpoint.. Mattermost Advisory ID: MMSA-2026-00671

Remediation

Vendor Solution

Update Mattermost to versions 11.8.0, 11.7.3, 10.11.20 or higher.

Tracking

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Advisories

No advisories available
References
History
Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Mattermost versions 11.7.x <= 11.7.2, 10.11.x <= 10.11.19 fail to sanitize team objects returned by the scheme teams endpoint, which allows a user with the User Manager role to obtain invite links for private teams and use them to join or share access to those teams via the scheme teams API endpoint.. Mattermost Advisory ID: MMSA-2026-00671
Title Mattermost schemes teams endpoint exposes private team invite IDs
Weaknesses CWE-862
References
Metrics cvssV3_1

{'score': 3.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Jul 13, 2026, 1:09 PM
Reserved
May 28, 2026, 11:26 AM
Status
Analyzed
Published
Jul 13, 2026, 11:16 AM
Modified
Jul 13, 2026, 8:38 PM