CVE-2026-55641 Details
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.
A vulnerability in 9Router versions prior to 0.5.2 allows remote, unauthenticated attackers to bypass API key authentication on the /v1 LLM proxy. This is achieved by manipulating the Host header to 'localhost', exploiting the application's trust in client-controlled input. The flaw arises because 9Router binds to all network interfaces by default, making it accessible from external sources. As a result, attackers can gain unauthorized access to the proxy, using the victim's stored provider credentials for calls to upstream AI services, or exploit the /v1/search endpoint to perform server-side requests to internal or cloud metadata hosts, with the response reflected back to them.
Users can update to 9Router version 0.5.2 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jul 10, 2026CISA-ADP
Assessed Jul 10, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/decolua/9router/security/advisories/GHSA-86m2-fcxq-5q7c | CISA-ADP | AdvisoryExploitRemedyVendor |
| https://github.com/decolua/9router/commit/b282f0554972ea35281520738759d76abcd0b0b3 | [email protected] | Source CodeVendor |
| https://github.com/decolua/9router/releases/tag/v0.5.2 | [email protected] | Release NotesVendor |
| https://github.com/decolua/9router/security/advisories/GHSA-86m2-fcxq-5q7c | [email protected] | AdvisoryExploitRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-1327 | Binding to an Unrestricted IP Address | [email protected] |
| CWE-290 | Authentication Bypass by Spoofing | [email protected] |
| CWE-348 | Use of Less Trusted Source | [email protected] |
| CWE-918 | Server-Side Request Forgery (SSRF) | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| decolua 9router | <= 0.4.80 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 10, 2026 | CVE Modified | CISA-ADP |
| Jul 10, 2026 | New CVE Received | [email protected] |