CVE-2026-55641

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

State: Published
Severity: 8.2 High
Published: Jul 10, 2026
Updated: Jul 10, 2026
Reserved: Jun 16, 2026

Description

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 exposes the /v1 proxy to upstream provider calls using stored provider credentials and allows /v1/search with the searxng provider_options.baseUrl parameter to drive server-side requests to internal or cloud-metadata hosts. This issue is fixed in version 0.5.2.

Scores

CVSS	Score	Vector	Source
3.1	8.2 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N	GitHub_M

Weaknesses

CWE-290 Authentication Bypass by Spoofing
CWE-348 Use of Less Trusted Source
CWE-918 Server-Side Request Forgery (SSRF)
CWE-1327 Binding to an Unrestricted IP Address

Affected Products

Product	Versions
9routerdecolua	< 0.5.2Affected

References

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