CVE-2026-79748: MCPHub Authentication Bypass Vulnerability

CVE-2026-79748 Overview

MCPHub, a unified hub for centrally managing and orchestrating Model Context Protocol (MCP) servers, contains a missing authorization vulnerability [CWE-862] that allows any authenticated user to execute arbitrary operating system commands. The flaw affects the POST /api/servers and PUT /api/servers/:name endpoints in versions prior to 0.12.15. These endpoints spawn a stdio process via child_process.spawn using attacker-controlled command and args fields, with no admin check and no allowlist. Any low-privilege authenticated user can trigger execution as the MCPHub OS user, which is typically root in the published Docker image and in npx or systemd deployments.

Critical Impact
Authenticated non-admin users can achieve remote code execution as root on the MCPHub host by submitting a crafted server configuration.

Affected Products

MCPHub versions prior to 0.12.15
MCPHub Docker image (runs as root)
MCPHub npx and systemd deployments

Discovery Timeline

2026-08-31 - CVE-2026-79748 published to NVD
2026-08-31 - Last updated in NVD database

Technical Details for CVE-2026-79748

Vulnerability Analysis

MCPHub exposes REST endpoints for creating and updating MCP server configurations. When a client calls POST /api/servers or PUT /api/servers/:name, the application stores the submitted configuration and immediately launches the referenced stdio process using Node.js child_process.spawn. Authentication is enforced, but authorization is not. The endpoints do not verify that the caller holds an administrative role and do not sanitize or restrict the command and args fields.

An authenticated attacker can submit a configuration containing command:"/bin/sh" (or any other binary present on the host) with arbitrary arguments. MCPHub spawns the specified process directly, giving the attacker command execution as the MCPHub server's OS user. In the published Docker image, npx runs, and typical systemd unit files, that user is root, which yields a full host compromise from a single authenticated API call.

Root Cause

The root cause is a broken access control defect. The server-management endpoints combine two dangerous properties: they trust any authenticated session as if it were an administrator, and they treat user-supplied command and args values as safe input to a process spawner. Missing an authorization layer on privileged administrative operations violates the principle of least privilege and maps directly to [CWE-862].

Attack Vector

Exploitation requires network access to the MCPHub API and any valid non-admin account. The attacker issues a single HTTP request to POST /api/servers containing a JSON body with command set to a shell binary and args set to attacker-controlled arguments. MCPHub persists the configuration and invokes child_process.spawn, launching the process. No user interaction, memory corruption primitive, or authentication bypass is required. See the GitHub Security Advisory GHSA-mx89-jjx9-gjr8 for full technical details.

Detection Methods for CVE-2026-79748

Indicators of Compromise

Unexpected POST /api/servers or PUT /api/servers/:name requests from non-admin accounts in MCPHub access logs
MCPHub parent process spawning shells such as /bin/sh, /bin/bash, or interpreters like python, node, or curl
New or modified MCP server entries in MCPHub configuration referencing shell binaries in the command field
Outbound network connections initiated by child processes of the MCPHub service

Detection Strategies

Alert on any child process of the MCPHub runtime whose executable path is not on an approved MCP server binary list
Correlate authenticated API requests to /api/servers with subsequent process creation events on the same host within a short time window
Baseline the set of accounts that normally call server-management endpoints and flag first-time callers

Monitoring Recommendations

Ingest MCPHub application logs and host process telemetry into a centralized analytics pipeline for correlation
Monitor container runtime events for MCPHub images spawning interactive shells or reverse shell patterns
Track file writes and cron or systemd modifications made by MCPHub child processes for persistence attempts

How to Mitigate CVE-2026-79748

Immediate Actions Required

Upgrade MCPHub to version 0.12.15 or later immediately across all deployments
Rotate any credentials, tokens, or secrets accessible from the MCPHub host, since prior compromise cannot be ruled out
Audit MCPHub user accounts and revoke access for any user that does not require server-management privileges
Review MCP server configuration history for unexpected command values referencing shells or interpreters

Patch Information

The issue is fixed in MCPHub version 0.12.15. See the GitHub Release v0.12.15 and the corresponding GitHub Pull Request for the code changes that introduce the authorization check and constrain the server-management endpoints.

Workarounds

Restrict network access to the MCPHub API to trusted administrative networks using a reverse proxy or firewall rules
Run the MCPHub container or process as a non-root, unprivileged OS user to reduce blast radius
Temporarily disable user self-registration and limit accounts to trusted administrators until the patch is applied
Deploy MCPHub inside a hardened container with a read-only filesystem and no shell binaries where feasible

bash

# Configuration example: upgrade MCPHub to the patched release
npm install -g @samanhappy/mcphub@0.12.15

# Or, for Docker deployments, pull the patched image and run as a non-root user
docker pull samanhappy/mcphub:0.12.15
docker run --user 1000:1000 --read-only samanhappy/mcphub:0.12.15