CVE-2026-49353 9Router: Local-Only Access Gate Bypass in 9router via Host Header SpoofING
Attackers can bypass local-only access controls via Host header spoofing in reverse proxy setups to execute code through MCP child processes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-49353?
CVE-2026-49353 is a high-severity authentication bypass vulnerability in decolua 9router, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
9Router is an AI router & token saver. In 0.4.45 and earlier, 9Router's src/dashboardGuard.js local-only access gate used Host and Origin headers in isLocalRequest() to protect /api/mcp/*, /api/tunnel/*, and /api/cli-tools/*, allowing header spoofing in reverse proxy or tunnel deployments to reach MCP child process stdin paths.
Weakness: CWE-290
Which versions are affected by CVE-2026-49353?
2 open source packages ship an affected version, including 9router.
| Package | Affected | Fixed in |
|---|---|---|
9router npm | All versions to 0.4.55 | None |
9router npm | All versions to 0.4.55 | None |
How do I fix CVE-2026-49353?
No fix has been published for CVE-2026-49353 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-49353 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49353 exists.
Sources
Also known as GHSA-6g2f-w7g3-77vf.