DoS in Calls plugin via malformed UTF-8 in WebSocket request
Priority LOW 29CWE-1287Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.
Summary
Mattermost versions 11.0.x <= 11.0.4, 10.12.x <= 10.12.2, 10.11.x <= 10.11.6 fail to check WebSocket request field for proper UTF-8 format, which allows attacker to crash Calls plug-in via sending malformed request.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00288 21st percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.1.0, 11.0.5, 10.12.3 +1github.com/mattermost/mattermost-plugin-calls (Go): 1.11.0
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 – 11.0.4; 10.12.0 – 10.12.2; 10.11.0 – 10.11.6 | 11.1.0, 11.0.5, 10.12.3, 10.11.7 | Patch available | CNA |
| — | github.com/mattermost/mattermost-plugin-calls (Go) | before 1.11.0 | 1.11.0 | Patch available | GHSA-j5vq-62gr-8v3r |
- Mattermost VendorMattermost Affected 11.0.0 – 11.0.4; 10.12.0 – 10.12.2; 10.11.0 – 10.11.6 Fixed in 11.1.0, 11.0.5, 10.12.3, 10.11.7 Patch available CNA
- github.com/mattermost/mattermost-plugin-calls (Go) Vendor— Affected before 1.11.0 Fixed in 1.11.0 Patch available GHSA-j5vq-62gr-8v3r
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | 10.11.0 to before 10.11.7; 10.12.0 to before 10.12.3; 11.0.0 to before 11.0.5 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 10.11.0 to before 10.11.7; 10.12.0 to before 10.12.3; 11.0.0 to before 11.0.5 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 11.1.0, 11.0.5, 10.12.3, 10.11.7
- Fix · GHSA-j5vq-62gr-8v3r github.com/mattermost/mattermost-plugin-calls (Go) Fixed in 1.11.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2025-12689
- 2026-10-03 Alias added: GHSA-j5vq-62gr-8v3r
References
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-2025-12689 · CVE Program
- CVE-2025-12689 · NVD
- FIRST EPSS
- GHSA-j5vq-62gr-8v3r · GitHub Advisory Database · CC BY 4.0
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