CVE-2026-46339

9Router: Unauthenticated Remote Code Execution via unprotected MCP custom plugin routes

Published Jul 15, 2026 CVSS 3.1 · 10 Critical EPSS 2.8% KEV · Not listed

Description

9Router is an AI router & token saver. From 0.4.30 until 0.4.37, 9Router's src/proxy.js middleware did not protect /api/cli-tools/* and /api/mcp/*, allowing unauthenticated registration of customPlugins through src/app/api/cli-tools/cowork-settings/route.js and command execution through the MCP bridge. This vulnerability is fixed in 0.4.37.

Analysis

Technical impact

The vulnerability exists in 9Router versions 0.4.30 through 0.4.36, where the middleware protecting /api/cli‑tools/* and /api/mcp/* was absent. This allowed unauthenticated users to register custom plugins via src/app/api/cli‑tools/cowork‑settings/route.js and then execute commands through the MCP bridge, leading to remote code execution. The weakness involves lack of authentication (CWE‑306) and operating‑system command injection (CWE‑78).

Affected Systems

The impacted product is 9Router from the vendor decolua. Versions 0.4.30 through 0.4.36 were vulnerable, and the issue was fixed starting with version 0.4.37. No other versions are listed as affected.

Risk and Exploitability

With a CVSS score of 10, the vulnerability offers a fully exploitable remote code execution path. The EPSS score of 2% indicates a low likelihood of exploitation, and the flaw has not yet appeared in the CISA KEV catalog. Attackers can reach the vulnerable endpoints via standard HTTP requests to the 9Router service, requiring no special network permissions beyond access to the exposed routes.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

decolua

9router

affected

Version	Status	Constraints
`>= 0.4.30, < 0.4.37`	affected	—

No data.

Vendor Product Versions

Decolua

9router

Version	Status	Scheme	Platform
`[0.4.30,0.4.37)`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade 9Router to version 0.4.37 or later to apply the vendor‑supplied fix.
If an upgrade is not immediately possible, block all traffic to /api/cli‑tools/* and /api/mcp/* using a firewall or reverse‑proxy, effectively disabling the vulnerable paths.
Review any custom plugins that have been installed; remove untrusted or unnecessary plugins and ensure that plugin configurations cannot be altered through unauthenticated endpoints.

Generated by OpenCVE AI on August 3, 2026 at 03:00 UTC.

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-fhh6-4qxv-rpqj	9router: Unauthenticated Remote Code Execution via unprotected MCP custom plugin routes

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: 2.8% (2.762% probability within 30 days)

Exploitation poc

Automatable yes

Technical Impact total

References

Link	Providers
https://github.com/decolua/9router/commit/992f4db4a0d858bcc86b4786f2abab117a6ccdf8
https://github.com/decolua/9router/security/advisories/GHSA-fhh6-4qxv-rpqj

History

Jul 16, 2026 1:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Jul 16, 2026 2:00 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Decolua Decolua 9router
Vendors & Products		Decolua Decolua 9router

Jul 15, 2026 9:00 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		9Router is an AI router & token saver. From 0.4.30 until 0.4.37, 9Router's src/proxy.js middleware did not protect /api/cli-tools/* and /api/mcp/*, allowing unauthenticated registration of customPlugins through src/app/api/cli-tools/cowork-settings/route.js and command execution through the MCP bridge. This vulnerability is fixed in 0.4.37.
Title		9Router: Unauthenticated Remote Code Execution via unprotected MCP custom plugin routes
Weaknesses		CWE-306 CWE-78
References		https://github.com/decolua/9router/commit/992f4db4a0d858bcc86b4786f2abab117a6ccdf8 https://github.com/decolua/9router/security/advisories/GHSA-fhh6-4qxv-rpqj
Metrics		cvssV3_1 `{'score': 10, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'}`