GHSA-4g87-9x45-cx2h CVE-2025-12559 GO-2025-4169
Mattermost fails to sanitize team email addresses
Medium
Go
- Severity
- 4.3 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.23%
- Chance of exploitation in the next 30 days. Higher than 14.10% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
- Fix
- Available
- 2 packages have a fixed version
Description
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
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/mattermost/mattermost-server | >= 11.0.0, < 11.0.3 |
11.0.3 |
| github.com/mattermost/mattermost-server | >= 10.12.0, < 10.12.2 |
10.12.2 |
| github.com/mattermost/mattermost-server | >= 10.11.0, < 10.11.5 |
10.11.5 |
| github.com/mattermost/mattermost-server | >= 10.5.0, < 10.5.13 |
10.5.13 |
| github.com/mattermost/mattermost-server | all versions |
No fix yet |
| github.com/mattermost/mattermost-server/v5 | all versions |
No fix yet |
| github.com/mattermost/mattermost-server/v6 | all versions |
No fix yet |
| github.com/mattermost/mattermost/server/v8 | < 8.0.0-20251015091448-abbf01b9db45 |
8.0.0-20251015091448-abbf01b9db45 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/mattermost/mattermost-server Go → 11.0.3
- go
go get github.com/mattermost/mattermost-server@v11.0.3 && go mod tidy
github.com/mattermost/mattermost/server/v8 Go → 8.0.0-20251015091448-abbf01b9db45
- go
go get github.com/mattermost/mattermost/server/v8@v8.0.0-20251015091448-abbf01b9db45 && go mod tidy
Severity breakdown
CVSS 3.1 4.3
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Weakness
CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
How to prevent it
- Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
References
Advisories
Packages
Other links
- github.com/mattermost/mattermost/pull/34110
- github.com/mattermost/mattermost/commit/5d8719042c1807da59ac8a821624eb01152d8495
- github.com/mattermost/mattermost/commit/649aee8fa9184ca59bd66022a33b8f8918e413aa
- github.com/mattermost/mattermost/commit/7ccb62db7958abd6a4b21a06c5a4f5367a8f8b1f
- github.com/mattermost/mattermost/commit/9f54e5cdc3aef412945ff0e6a58338f7b549bdda
- github.com/mattermost/mattermost/commit/abbf01b9db45d1850eaf3701ea8362b910193ffd
- mattermost.com/security-updates
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-xmfh-3ccg-c9fx Mattermost has an Incorrect Authorization issue | Low | Also affects github.com/mattermost/mattermost-server |
| GHSA-h998-hxxj-8q83 Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-g5vr-6pgg-74qv Mattermost doesn't enforce bot-specific permission checks on the user active status endpoint | Low | Also affects github.com/mattermost/mattermost-server |
| GHSA-jqgv-39mg-7c2r Mattermost doesn't authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-mxq2-5jpg-7474 Mattermost doesn't validate channel ownership of an existing subscription before applying edits | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-2g8v-grq3-hq2g Mattermost doesn't enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-6hxm-w4hv-vgvw Mattermost doesn't require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints | High | Also affects github.com/mattermost/mattermost-server |
| GHSA-9p44-r552-4wp9 Mattermost doesn't sanitize the Remote Cluster API response on PATCH operations | Medium | Also affects github.com/mattermost/mattermost-server |
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