CVE-2026-55641
9router: Unauthenticated `/v1` proxy access via `Host`-header spoofing → open AI relay + SSRF
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.
INFO
Published Date :
July 10, 2026, 5:16 p.m.
Last Modified :
Oct. 25, 2026, 3:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update 9Router to version 0.5.2 or later.
- Verify authentication bypass is no longer possible.
- Review provider and proxy configurations.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55641.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55641 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55641
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55641 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55641 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: 9router de decolua, Description: 9Router es un router de IA y ahorrador de tokens. Antes de la versión 0.5.2, 9router determina si una solicitud de proxy LLM /v1 es local leyendo el encabezado Host controlado por el cliente, permitiendo a un atacante remoto no autenticado enviar Host: localhost y omitir la autenticación por clave de API. En la configuración predeterminada, esto expone el proxy /v1 a llamadas de proveedores ascendentes utilizando credenciales de proveedor almacenadas y permite /v1/search con el parámetro searxng provider_options.baseUrl para dirigir solicitudes del lado del servidor a hosts internos o de metadatos en la nube. Este problema está solucionado en la versión 0.5.2. -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 10, 2026
Action Type Old Value New Value Added Reference https://github.com/decolua/9router/security/advisories/GHSA-86m2-fcxq-5q7c Added SSVC {'id': 'CVE-2026-55641', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-10T19:06:04.625545Z'} -
New CVE Received by [email protected]
Jul. 10, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'decolua', 'product': '9router', 'versions': [{'status': 'affected', 'version': '< 0.5.2'}]}] Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N Added CWE CWE-918 Added CWE CWE-290 Added CWE CWE-348 Added CWE CWE-1327 Added Reference https://github.com/decolua/9router/commit/b282f0554972ea35281520738759d76abcd0b0b3 Added Reference https://github.com/decolua/9router/releases/tag/v0.5.2 Added Reference https://github.com/decolua/9router/security/advisories/GHSA-86m2-fcxq-5q7c