9Router: Unauthenticated Remote Code Execution via unprotected MCP custom plugin routes
Priority HIGH 82CWE-306Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass, Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-306 and CWE-78.
Summary
9Router is an AI router & token saver. From 0.4.30 until 0.4.37, 9Router's src/proxy.js middleware did not protect /api/cli-tools/* and /api/mcp/*, allowing unauthenticated registration of customPlugins through src/app/api/cli-tools/cowork-settings/route.js and command execution through the MCP bridge. This vulnerability is fixed in 0.4.37.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.02762 86th percentileScored 2026-11-07
Fix Fixed 9router (decolua): 0.4.379router (npm): 0.4.37
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Total
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 |
|---|---|---|---|---|---|
| decolua | 9router | 0.4.30 to before 0.4.37 | 0.4.37 | Patch available | CNA |
| — | 9router (npm) | 0.4.30 to before 0.4.37 | 0.4.37 | Patch available | GHSA-fhh6-4qxv-rpqj |
- 9router Vendordecolua Affected 0.4.30 to before 0.4.37 Fixed in 0.4.37 Patch available CNA
- 9router (npm) Vendor— Affected 0.4.30 to before 0.4.37 Fixed in 0.4.37 Patch available GHSA-fhh6-4qxv-rpqj
Remediation
- Fix · CNA 9router (decolua) Fixed in 0.4.37
- Fix · GHSA-fhh6-4qxv-rpqj 9router (npm) Fixed in 0.4.37 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-46339
- 2026-10-03 Alias added: GHSA-fhh6-4qxv-rpqj
References
More decolua vulnerabilities
- TI-2026-36526 9Router: Hardcoded Default fallback JWT Secret Allows Authentication Bypass CVSS 3.1CRITICAL 9.8
- TI-2026-44499 9Router 0.4.41 - Unauthenticated API Key Exposure via /api/usage/stats CVSS 4.0CRITICAL 9.3
- TI-2026-42622 9Router 0.4.41 - Unauthenticated API Exposure via /api/providers CVSS 4.0CRITICAL 9.3
- TI-2026-44500 9Router 0.4.41 - Unauthenticated Information Disclosure via API Usage Endpoints CVSS 4.0HIGH 8.7
- TI-2026-40860 9Router: Authenticated Server-Side Request Forgery (SSRF) via OIDC Provider Test Endpoint CVSS 3.1HIGH 8.6
- TI-2026-40165 9router: Unauthenticated LLM proxy access via /codex rewrite authorization bypass CVSS 3.1HIGH 8.6
Sources
- CVE-2026-46339 · CVE Program
- CVE-2026-46339 · NVD
- FIRST EPSS
- GHSA-fhh6-4qxv-rpqj · 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