Live Exposure Defense: From CVE to Confirmed Exposure in 12 Hours – See more

Back
New CVE Detected

CVE-2026-46339 – Unauthenticated RCE – 9Router 0.4.30–0.4.36

Be the first to know when new zero-days emerge:

Subscribe to Email Alerts
Subscribe to RSS Feed

Summary

CVE-2026-46339 is a critical unauthenticated remote code execution vulnerability (CVSS 10.0) in 9Router, an AI routing and token-saving proxy tool developed by decolua. The flaw exists in the tool’s Next.js middleware (src/proxy.js), which enforces authentication on only a narrow set of explicitly listed routes while leaving the entire /api/cli-tools/* and /api/mcp/* route namespaces completely unprotected — enabling any remote, unauthenticated attacker to register a malicious plugin and execute arbitrary OS commands on the host. The vulnerability affects versions 0.4.30 through 0.4.36 and is fixed in version 0.4.37.

Technical details

  • Root cause: The Next.js middleware in src/proxy.js enforces authentication checks against only 8 explicitly listed routes. The /api/cli-tools/* and /api/mcp/* namespaces — comprising 40+ routes — receive no authentication whatsoever, classified under CWE-306 (Missing Authentication for Critical Function) and CWE-78 (OS Command Injection).
  • Trigger conditions: No authentication, special configuration, or user interaction is required. Any attacker with network access to the 9Router instance can exploit this vulnerability immediately.
  • Attack chain: Exploitation is a two-request sequence — (1) an unauthenticated POST to /api/cli-tools/cowork-settings registers a malicious customPlugin entry with attacker-controlled command and args fields, stored in a process-global registry with no input validation; (2) an unauthenticated GET to /api/mcp/[plugin]/sse triggers spawn() on the stored command, executing arbitrary OS commands on the host. The full exploit chain completes in under two seconds.
  • Impact: Arbitrary OS command execution as the process user; full filesystem read and write access enabling exfiltration of stored secrets (API keys, OAuth tokens, cloud credentials, and provider configurations); process termination; and potential container escape if the process user holds Docker group membership.

Affected software

  • 9Router (npm package 9router, vendor: decolua): versions 0.4.30 through 0.4.36 (inclusive)

Severity

  • CVSS v3.1 Base Score: 10.0 (Critical)
  • Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Mitigation and recommended actions

  • Immediate action: Upgrade 9Router to version 0.4.37 or later. Version 0.4.37 extends the middleware matcher to enforce authentication on /api/cli-tools/:path* and /api/mcp/:path* endpoints.
  • If immediate patching is not feasible: Restrict network-level access to the 9Router instance (default port: 20128) using firewall rules or network controls, permitting only explicitly trusted sources. Note that a known bug in affected versions causes the server to bind to all interfaces (0.0.0.0) even when --host 127.0.0.1 is specified at launch, meaning host-level binding flags alone cannot be relied upon as a compensating control.

IONIX Status

The IONIX research team is tracking ongoing exploitation attempts and recommends immediate patching. Potentially affected assets are outlined in this post.

References

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report

How IONIX’s External Exposure Management Platform Detects and Validates
Zero-Days to Shrink MTTR

1

Map your entire attack surface (continously)

IONIX uses multi-factor discovery methods, including DNS analysis, certificate mapping, metadata inspection, and more, to automatically map every internet-facing asset across your environment. This includes cloud instances, third-party platforms, shadow IT, and even forgotten infrastructure that traditional tools miss.

2

Monitor for new CVEs

Dozens of threat intel feeds using agentic technology are continuously analyzed to detect the appearance of proof-of-concept code, exploit kits, and indicators of active targeting. IONIX goes further by applying AI to proactively evaluate whether emerging vulnerabilities are likely to be exploited, even before PoCs go public.

3

Identify Potential External Exposures

Not all CVEs matter. IONIX filters vulnerabilities by asking attacker-centric questions: Can it be reached from the internet? Does it require authentication? Is it being exploited in the wild? This dramatically reduces noise and focuses teams on threats that can actually be weaponized.

4

Create Safe, Scalable Exploit Validations

IONIX transforms real-world PoCs into safe, non-intrusive test payloads that can be run in production environments without disruption. These simulations are precisely targeted to the systems that are vulnerable, ensuring rapid validation without unnecessary load.

5

Execute Exploit Validations

By combining context about software stack, versioning, exposure status, and reachability, IONIX ensures that only the right payloads are executed against the right assets, maximizing efficiency and minimizing risk.

6

Drive Fast and Actionable Remediation

Results are routed through integrations with ticketing, SOAR, and SIEM tools. Issues are written in plain language, bundled into remediation clusters, and prioritized based on asset criticality, exploitability, and blast radius. This shortens mean time to remediation (MTTR) and empowers teams to act with confidence.

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report
Close

Subscribe to Threat Center RSS

Copy/paste the link below into your preferred RSS reader or follow these instructions to subscribe to Slack alerts.

Open RSS feedSlack setup instructions

Close

Get Real-Time CVE Alerts to Your Email

Be the first to know when new zero-days emerge