CVE-2025-12559: Information Disclosure in Common Teams API

Published Nov 27, 2025
·
Updated

Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to sanitize team email addresses to be visible only to Team Admins, which allows any authenticated user to view team email addresses via the GET /api/v4/channels/{channelid}/commonteams endpoint

Affected Software

10 affected componentsFixes available
Mattermost Mattermost<=11.0.2, <=10.12.1, <=10.11.4, <=10.5.12
go/github.com/mattermost/mattermost-server>=10.5.0<10.5.13
10.5.13
go/github.com/mattermost/mattermost-server>=10.11.0<10.11.5
10.11.5
go/github.com/mattermost/mattermost-server>=10.12.0<10.12.2
10.12.2
go/github.com/mattermost/mattermost-server>=11.0.0<11.0.3
11.0.3
go/github.com/mattermost/mattermost/server/v8<8.0.0-20251015091448-abbf01b9db45
8.0.0-20251015091448-abbf01b9db45
Mattermost Mattermost Server>=10.5.0<10.5.13
Mattermost Mattermost Server>=10.11.0<10.11.5
Mattermost Mattermost Server>=10.12.0<10.12.2
Mattermost Mattermost Server>=11.0.0<11.0.3

Remediation

Information

Update Mattermost to versions 11.1.0, 11.0.3, 10.12.2, 10.11.5, 10.5.13 or higher.

Event History

Nov 27, 2025
CVE Published
via MITRE·04:36 PM
Data Sourced
via MITRE·04:36 PM
RemedyDescriptionSeverityWeakness
Data Sourced
via NVD·05:15 PM
DescriptionSeverityWeaknessAffected Software
Advisory Published
via GitHub·06:30 PM
Data Sourced
via GitHub·06:30 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2025-12559?

CVE-2025-12559 has a medium severity level due to the potential exposure of sensitive email addresses.

2

How do I fix CVE-2025-12559?

To fix CVE-2025-12559, upgrade your Mattermost installation to version 11.0.3 or later, or 10.12.2 or later.

3

What are the affected versions of Mattermost for CVE-2025-12559?

Affected versions for CVE-2025-12559 are Mattermost 11.0.x up to 11.0.2, 10.12.x up to 10.12.1, 10.11.x up to 10.11.4, and 10.5.x up to 10.5.12.

4

What type of data is exposed in CVE-2025-12559?

CVE-2025-12559 allows authenticated users to view team email addresses that should only be visible to Team Admins.

5

Can CVE-2025-12559 be exploited without authentication?

No, CVE-2025-12559 requires an authenticated user to exploit the vulnerability.

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203