CVE-2025-65719: Kubectl MCP Server RCE Vulnerability

CVE-2025-65719 Overview

CVE-2025-65719 is a code injection vulnerability [CWE-94] in the open source Kubectl MCP Server version 1.1.1. The flaw allows remote attackers to execute arbitrary code on a victim system when a user interacts with a crafted HTML page. The Kubectl MCP Server provides Model Context Protocol (MCP) integration for managing Kubernetes clusters through kubectl commands, often invoked by AI assistants and developer tools. Successful exploitation grants attackers the same privileges as the user running the MCP server, including the ability to interact with connected Kubernetes clusters.

Critical Impact

Attackers can achieve remote code execution on hosts running Kubectl MCP Server v1.1.1 by luring users to a malicious web page, potentially pivoting into managed Kubernetes environments.

Affected Products

• Open Source Kubectl MCP Server v1.1.1
• Deployments integrating kubectl-mcp-server with AI assistants or developer tooling
• Kubernetes environments managed through the affected MCP server instance

Discovery Timeline

• 2026-05-12 - CVE-2025-65719 published to the National Vulnerability Database
• 2026-05-13 - Last updated in NVD database

Technical Details for CVE-2025-65719

Vulnerability Analysis

The vulnerability resides in how Kubectl MCP Server v1.1.1 processes input that originates from web content. Because the MCP server exposes interfaces invoked by AI assistants and browsers, a crafted HTML page can deliver attacker-controlled content that the server interprets as executable code. The issue is classified as Improper Control of Generation of Code [CWE-94], commonly known as code injection. The attack succeeds over the network, requires no authentication, and triggers when the victim interacts with the malicious page. Once execution succeeds, the attacker runs commands under the privileges of the MCP server process.

Root Cause

The root cause is insufficient sanitization and validation of inputs that flow from web-originated content into command or code execution paths. MCP servers expose tool-calling primitives, and when these primitives are reachable from browser contexts without strict origin and content controls, attacker-supplied payloads can be reflected into shell or interpreter execution. The lack of input boundary enforcement between untrusted HTML content and the local MCP execution context is the underlying defect.

Attack Vector

The attack requires a victim to visit or interact with a crafted HTML page while the Kubectl MCP Server is running locally or on a reachable host. The malicious page issues requests that the MCP server processes, embedding attacker-controlled parameters into command execution. The attacker does not need credentials or prior access to the target system. After code execution, the attacker can run arbitrary kubectl commands against connected clusters, exfiltrate kubeconfig credentials, or deploy malicious workloads. Technical analysis is available in the OX Security CVE-2025-65719 Analysis and the Kubectl MCP Server repository.

No verified public exploit code is referenced in the advisory. See the technical write-ups linked above for proof-of-concept details.

Detection Methods for CVE-2025-65719

Indicators of Compromise

• Unexpected kubectl invocations originating from the MCP server process, especially commands targeting secrets, serviceaccounts, or workload creation
• Outbound HTTP requests from browsers to local MCP server ports immediately followed by anomalous child processes
• New or modified Kubernetes resources (Deployments, DaemonSets, CronJobs) created without a corresponding CI/CD or operator change
• Access to ~/.kube/config or kubeconfig files by processes other than approved Kubernetes tooling

Detection Strategies

• Monitor process creation events where the MCP server binary spawns shells, interpreters, or unexpected binaries
• Inspect web server and proxy logs for browser-initiated requests to MCP server endpoints that include shell metacharacters or command fragments
• Correlate Kubernetes audit logs with host-level process telemetry to identify cluster actions that lack a legitimate user-driven origin

Monitoring Recommendations

• Enable Kubernetes audit logging at the Metadata level or higher and forward events to a central analytics platform
• Track network connections from browser processes to localhost ports bound by kubectl-mcp-server
• Alert on first-seen parent-child process relationships involving the MCP server binary

How to Mitigate CVE-2025-65719

Immediate Actions Required

• Stop or uninstall Kubectl MCP Server v1.1.1 instances until a fixed release is verified
• Rotate kubeconfig credentials, service account tokens, and cloud provider credentials that the MCP server could access
• Restrict the MCP server to bind only to loopback interfaces and require strict origin checks from any client
• Review recent Kubernetes audit logs for unauthorized resource changes during the exposure window

Patch Information

No official patched version is referenced in the NVD entry at publication time. Monitor the Kubectl MCP Server repository for updated releases and consult the OX Security advisory for remediation guidance. Until a verified fix is published, treat all v1.1.1 deployments as vulnerable.

Workarounds

• Run the MCP server inside a sandboxed container with no host filesystem access and a least-privilege kubeconfig
• Block browser access to MCP server ports using host firewall rules or browser extension policies
• Disable the MCP integration in AI assistants and developer tools that connect to kubectl-mcp-server
• Apply network segmentation so that the MCP server cannot reach production Kubernetes API endpoints

# Configuration example: restrict MCP server to loopback and isolate via firewall
# 1. Bind MCP server to localhost only (example wrapper)
export MCP_BIND_ADDRESS=127.0.0.1
export MCP_BIND_PORT=8080

# 2. Block external access with iptables
sudo iptables -A INPUT -p tcp --dport 8080 ! -i lo -j DROP

# 3. Run with a scoped kubeconfig (read-only, namespace-restricted)
export KUBECONFIG=/etc/mcp/readonly-kubeconfig.yaml