Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Suyogs | Mcp-Server-Kubernetes | < 3.5.0 |
Related Weaknesses (CWE)
References
- https://github.com/Flux159/mcp-server-kubernetes/releases/tag/v3.5.0ProductRelease Notes
- https://github.com/Flux159/mcp-server-kubernetes/security/advisories/GHSA-4xqg-gMitigationVendor Advisory
- https://github.com/Flux159/mcp-server-kubernetes/security/advisories/GHSA-4xqg-gMitigationVendor Advisory
FAQ
What is CVE-2026-39884?
CVE-2026-39884 is a vulnerability with a CVSS score of 8.3 (HIGH). 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/p...
How severe is CVE-2026-39884?
CVE-2026-39884 has been rated HIGH with a CVSS base score of 8.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-39884?
Check the references section above for vendor advisories and patch information. Affected products include: Suyogs Mcp-Server-Kubernetes.