Skip to main content
← All vulnerabilities
CVE-2026-39884GHSA-4XQG-GF5C-GHWQ

MCP Server Kubernetes has Argument Injection in its port_forward tool via space-splitting

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 3.5.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: no
  • Technical impact: total

Summary

mcp-server-kubernetes is a Model Context Protocol server for Kubernetes cluster management. Versions 3.4.0 and prior contain an argument injection vulnerability in the port_forward tool in src/tools/port_forward.ts, where a kubectl command is constructed via string concatenation with user-controlled input and then naively split on spaces before being passed to spawn(). Unlike all other tools in the codebase which correctly use array-based argument passing with execFileSync(), port_forward treats every space in user-controlled fields (namespace, resourceType, resourceName, localPort, targetPort) as an argument boundary, allowing an attacker to inject arbitrary kubectl flags. This enables exposure of internal Kubernetes services to the network by injecting --address=0.0.0.0, cross-namespace targeting by injecting additional -n flags, and indirect exploitation via prompt injection against AI agents connected to the MCP server. This issue has been fixed in version 3.5.0.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Flux159 mcp-server-kubernetes

    fixed in 3.5.0

  • mcp-server-kubernetesnpm

    fixed in 3.5.0

References 2

GitHub · Flux159/mcp-server-kubernetes