9Router is an AI router & token saver. Prior to 0.5.6, 9Router deployments that allow requests to reach Next.js without the sanitizing custom-server.js wrapper trust the client-supplied X-9r-Real-Ip header in src/dashboardGuard.js when isLocalRequest decides whether canAccessPublicLlmApi may skip API-key validation for /api/v1/* routes. A remote unauthenticated attacker can set X-9r-Real-Ip to 127.0.0.1 and be classified as a local client, including on the verified GET /api/v1/models route.
This permits unauthorized use of the instance owner's configured LLM providers, consumption of paid credits, and enumeration of configured providers and models. This issue is fixed in version 0.5.6.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
Low
Partial disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 3
https://github.com/decolua/9router/commit/efd20be8d81ef2e256a7037f3aa78e6b567b5…
security-advisories@github.com
https://github.com/decolua/9router/releases/tag/v0.5.6
security-advisories@github.com
https://github.com/decolua/9router/security/advisories/GHSA-5mj8-gf6m-fhw8
security-advisories@github.com