User Impersonation

Overview 9router is a 9Router CLI - Start and manage 9Router server Affected versions of this package are vulnerable to User Impersonation via manipulation of the Host header. An attacker can gain unauthorized access to the /v1 proxy and trigger server-side requests to internal or cloud-metadata...

CVE-2026-55641 9router: Unauthenticated `/v1` proxy access via `Host`-header spoofing → open AI relay + SSRF

9Router is an AI router & token saver. Prior to 0.5.2, 9router determines whether a /v1 LLM proxy request is local by reading the client-controlled Host header, allowing a remote unauthenticated attacker to send Host: localhost and bypass API-key authentication. In the default configuration, this...

CVE-2026-55641

9router (affected component: /v1 LLM proxy logic) had an unauthenticated bypass due to client-controlled Host header processing before version 0.5.2. This allowed a remote attacker to craft Host: localhost to bypass API-key checks, potentially enabling upstream provider calls with stored credenti...