Vulnerability · Published Jul 10, 2026 · Assigned by GitHub_M

CVE-2026-556419router: Unauthenticated `/v1` proxy access via `Host`-header spoofing → open AI relay + SSRF

High 8.2

In plain English

A high-severity authentication bypass by spoofing in 9router from decolua. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High

Exploit odds (30 days)0.3%top 74.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	9router	0.5.2	GHSA-86m2-fcxq-5q7c

Affected products (as reported)

Vendor	Product	Versions
decolua	9router	< 0.5.2

Weakness: CWE-290, CWE-348, CWE-918, CWE-1327 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

References

https://github.com/decolua/9router/security/advisories/GHSA-86m2-fcxq-5q7c x_refsource_CONFIRM
https://github.com/decolua/9router/commit/b282f0554972ea35281520738759d76abcd0b0b3 x_refsource_MISC
https://github.com/decolua/9router/releases/tag/v0.5.2 x_refsource_MISC