CVE-2026-62312
9Router: Authenticated RCE via Unvalidated MCP Plugin Arguments
CVSS Score
8.8
EPSS Score
0.0%
EPSS Percentile
0th
9Router is an AI router & token saver. Prior to 0.5.2, 9Router allows a remote authenticated attacker to achieve arbitrary code execution on the host operating system by combining a Host header bypass of localhost-only routes with unvalidated MCP plugin args passed to child_process.spawn(), allowing malicious custom plugins to execute commands through /api/mcp//sse. This issue is fixed in version 0.5.2.
| CWE | CWE-78 |
| Vendor | decolua |
| Product | 9router |
| Published | Jul 15, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
decolua / 9router
< 0.5.2