CVE-2026-62312 9Router: Authenticated RCE via Unvalidated MCP Plugin Arguments
Authenticated attackers can execute arbitrary code on the host by bypassing localhost restrictions and injecting commands via unvalidated MCP plugin arguments.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-62312?
CVE-2026-62312 is a high-severity command injection vulnerability in decolua 9router, published on 15 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-78
Which versions are affected by CVE-2026-62312?
How do I fix CVE-2026-62312?
No fix has been published for CVE-2026-62312 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-62312 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62312 exists.
Sources
Also known as GHSA-63p9-g54h-prrp.