Mattermost 10.x-11.x: Email Addresses Exposed via /api/v4/channels Endpoint
CVE-2025-12559 Published on November 27, 2025
Information Disclosure in Common Teams API
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/{channel_id}/common_teams endpoint
Vulnerability Analysis
CVE-2025-12559 can be exploited with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a small impact on integrity and availability.
Weakness Type
What is an Information Disclosure Vulnerability?
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
CVE-2025-12559 has been classified to as an Information Disclosure vulnerability or weakness.
Products Associated with CVE-2025-12559
Want to know whenever a new CVE is published for MatterMost? stack.watch will email you.
Affected Versions
Mattermost:- Version 11.0.0, <= 11.0.2 is affected.
- Version 10.12.0, <= 10.12.1 is affected.
- Version 10.11.0, <= 10.11.4 is affected.
- Version 10.5.0, <= 10.5.12 is affected.
- Version 11.1.0 is unaffected.
- Version 11.0.3 is unaffected.
- Version 10.12.2 is unaffected.
- Version 10.11.5 is unaffected.
- Version 10.5.13 is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.