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CVE-2025-12559 Moderate

Mattermost fails to sanitize team email addresses in github.com/mattermost/mattermost-server

Mattermost fails to sanitize team email addresses in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. (If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.) The additional affected modules and versions are: github.com/mattermost/mattermost-server from v10.5.0 before v10.5.13, from v10.11.0 before v10.11.5, from v10.12.0 before v10.12.2, from v11.0.0 before v11.0.3.

Exploit probability 0.2%
Published December 15, 2025
Required by Not available
Last source change March 3, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown

116 explicit affected versions

Go github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server/v5
Go github.com/mattermost/mattermost-server/v6
Go github.com/mattermost/mattermost/server/v8
Go github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost/server/v8

03 / CONNECTIONS

Connected vulnerabilities

related OPENSUSE-SU-2026:21483-1

04 / EVIDENCE

Source records

Open Source Vulnerabilities CVE-2025-12559

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

View original source
Open Source Vulnerabilities GO-2025-4169

Mattermost fails to sanitize team email addresses in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. (If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.) The additional affected modules and versions are: github.com/mattermost/mattermost-server from v10.5.0 before v10.5.13, from v10.11.0 before v10.11.5, from v10.12.0 before v10.12.2, from v11.0.0 before v11.0.3.

View original source
Open Source Vulnerabilities GHSA-4g87-9x45-cx2h

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

View original source

05 / REFERENCES

Further evidence