Vulnerability · Published Jul 15, 2026 · Assigned by GitHub_M
CVE-2026-493539Router: Local-Only Access Gate Bypass in 9router via Host Header SpoofING
High 7.5
In plain English
A high-severity authentication bypass by spoofing in 9router from decolua. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities).
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.3%top 73.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | 9router | no fix listed | GHSA-6g2f-w7g3-77vf |
Affected products (as reported)
Weakness: CWE-290 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
References
- https://github.com/decolua/9router/security/advisories/GHSA-6g2f-w7g3-77vf x_refsource_CONFIRM
- https://github.com/decolua/9router/commit/5e1c1261368e06dced1cbc650684561b2c8844db x_refsource_MISC
- https://github.com/decolua/9router/commit/bb86808582067e4fc6f004508a919efb9970d1d5 x_refsource_MISC
- https://github.com/decolua/9router/releases/tag/v0.4.46 x_refsource_MISC