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TI-2026-40168 Aliases CVE-2026-55641GHSA-86m2-fcxq-5q7c

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

Priority HIGH 75CWE-1327Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-290.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00326 25th percentileScored 2026-11-07
Fix Fixed 9router (decolua): 0.5.29router (npm): 0.5.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
decolua9routerbefore 0.5.20.5.2Patch availableCNA
—9router (npm)before 0.5.20.5.2Patch availableGHSA-86m2-fcxq-5q7c
  • 9router Vendordecolua Affected before 0.5.2 Fixed in 0.5.2 Patch available CNA
  • 9router (npm) Vendor— Affected before 0.5.2 Fixed in 0.5.2 Patch available GHSA-86m2-fcxq-5q7c

Remediation

  • Fix · CNA 9router (decolua) Fixed in 0.5.2
  • Fix · GHSA-86m2-fcxq-5q7c 9router (npm) Fixed in 0.5.2 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55641
  2. 2026-10-03 Alias added: GHSA-86m2-fcxq-5q7c

References

Advisory 1

Other 4

  • TI-2026-36526 9Router: Hardcoded Default fallback JWT Secret Allows Authentication Bypass CVSS 3.1CRITICAL 9.8
  • TI-2026-34059 9Router: Unauthenticated Remote Code Execution via unprotected MCP custom plugin routes CVSS 3.1CRITICAL 10.0
  • TI-2026-44499 9Router 0.4.41 - Unauthenticated API Key Exposure via /api/usage/stats CVSS 4.0CRITICAL 9.3
  • TI-2026-42622 9Router 0.4.41 - Unauthenticated API Exposure via /api/providers CVSS 4.0CRITICAL 9.3
  • TI-2026-44500 9Router 0.4.41 - Unauthenticated Information Disclosure via API Usage Endpoints CVSS 4.0HIGH 8.7
  • TI-2026-40860 9Router: Authenticated Server-Side Request Forgery (SSRF) via OIDC Provider Test Endpoint CVSS 3.1HIGH 8.6
See all 25 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences