Information Disclosure in Common Teams API
Priority LOW 20CWE-200Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-200.
Summary
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
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00232 14th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.1.0, 11.0.3, 10.12.2 +2github.com/mattermost/mattermost/server/v8 (Go): 8.0.0-20251015091448-abbf01b9db45+1 more product
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Mattermost | Mattermost | 11.0.0 – 11.0.2; 10.12.0 – 10.12.1; 10.11.0 – 10.11.4; 10.5.0 – 10.5.12 | 11.1.0, 11.0.3, 10.12.2, 10.11.5, 10.5.13 | Patch available | CNA |
| — | github.com/mattermost/mattermost/server/v8 (Go) | before 8.0.0-20251015091448-abbf01b9db45 | 8.0.0-20251015091448-abbf01b9db45 | Patch available | GHSA-4g87-9x45-cx2h |
| — | github.com/mattermost/mattermost-server (Go) | 11.0.0 to before 11.0.3 | 11.0.3 | Patch available | GHSA-4g87-9x45-cx2h |
| — | github.com/mattermost/mattermost-server (Go) | 10.12.0 to before 10.12.2 | 10.12.2 | Patch available | GHSA-4g87-9x45-cx2h |
| — | github.com/mattermost/mattermost-server (Go) | 10.11.0 to before 10.11.5 | 10.11.5 | Patch available | GHSA-4g87-9x45-cx2h |
| — | github.com/mattermost/mattermost-server (Go) | 10.5.0 to before 10.5.13 | 10.5.13 | Patch available | GHSA-4g87-9x45-cx2h |
- Mattermost VendorMattermost Affected 11.0.0 – 11.0.2; 10.12.0 – 10.12.1; 10.11.0 – 10.11.4; 10.5.0 – 10.5.12 Fixed in 11.1.0, 11.0.3, 10.12.2, 10.11.5, 10.5.13 Patch available CNA
- github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected before 8.0.0-20251015091448-abbf01b9db45 Fixed in 8.0.0-20251015091448-abbf01b9db45 Patch available GHSA-4g87-9x45-cx2h
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 11.0.0 to before 11.0.3 Fixed in 11.0.3 Patch available GHSA-4g87-9x45-cx2h
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.12.0 to before 10.12.2 Fixed in 10.12.2 Patch available GHSA-4g87-9x45-cx2h
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.11.0 to before 10.11.5 Fixed in 10.11.5 Patch available GHSA-4g87-9x45-cx2h
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.5.0 to before 10.5.13 Fixed in 10.5.13 Patch available GHSA-4g87-9x45-cx2h
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | 10.5.0 to before 10.5.13; 10.11.0 to before 10.11.5; 10.12.0 to before 10.12.2; 11.0.0 to before 11.0.3 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 10.5.0 to before 10.5.13; 10.11.0 to before 10.11.5; 10.12.0 to before 10.12.2; 11.0.0 to before 11.0.3 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 11.1.0, 11.0.3, 10.12.2, 10.11.5, 10.5.13
- Fix · GHSA-4g87-9x45-cx2h github.com/mattermost/mattermost/server/v8 (Go) Fixed in 8.0.0-20251015091448-abbf01b9db45 Advisory →
- Fix · GHSA-4g87-9x45-cx2h github.com/mattermost/mattermost-server (Go) Fixed in 11.0.3 Advisory →
- Fix · GHSA-4g87-9x45-cx2h github.com/mattermost/mattermost-server (Go) Fixed in 10.12.2 Advisory →
- Fix · GHSA-4g87-9x45-cx2h github.com/mattermost/mattermost-server (Go) Fixed in 10.11.5 Advisory →
- Fix · GHSA-4g87-9x45-cx2h github.com/mattermost/mattermost-server (Go) Fixed in 10.5.13 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2025-12559
- 2026-10-03 Alias added: GHSA-4g87-9x45-cx2h
References
Other 7
- https://github.com/mattermost/mattermost/pull/34110
- https://github.com/mattermost/mattermost/commit/5d8719042c1807da59ac8a821624eb01152d8495
- https://github.com/mattermost/mattermost/commit/649aee8fa9184ca59bd66022a33b8f8918e413aa
- https://github.com/mattermost/mattermost/commit/7ccb62db7958abd6a4b21a06c5a4f5367a8f8b1f
- https://github.com/mattermost/mattermost/commit/9f54e5cdc3aef412945ff0e6a58338f7b549bdda
- https://github.com/mattermost/mattermost/commit/abbf01b9db45d1850eaf3701ea8362b910193ffd
- https://github.com/mattermost/mattermost
More Mattermost Server vulnerabilities
- TI-2025-18933 Arbitrary file read in Mattermost Boards via import & export board archive CVSS 3.1CRITICAL 9.9
- TI-2025-04465 Path Traversal Leading to RCE by Any Authenticated Mattermost User CVSS 3.1CRITICAL 9.9
- TI-2017-14068 An issue was discovered in Mattermost Server before 3.6.2. CVSS 3.1CRITICAL 9.8
- TI-2017-14060 An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. CVSS 3.1CRITICAL 9.8
- TI-2017-14048 An issue was discovered in Mattermost Server before 4.1.0, 4.0.4, and 3.10.3. CVSS 3.1CRITICAL 9.8
- TI-2025-14360 Arbitrary file read via block duplication in Mattermost Boards CVSS 3.1CRITICAL 9.9
Sources
- CVE-2025-12559 · CVE Program
- CVE-2025-12559 · NVD
- FIRST EPSS
- GHSA-4g87-9x45-cx2h · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences