Summary
MCP Inspector proxy server lacks authentication between the Inspector client and proxy
Versions of MCP Inspector below 0.14.1 are vulnerable to remote code execution due to lack of authentication between the Inspector client and proxy, allowing unauthenticated requests to launch MCP commands over stdio. Users should immediately upgrade to version 0.14.1 or later to address these vulnerabilities.
Credit: Rémy Marot [email protected]
Impact
A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-49596? CVE-2025-49596 is a critical-severity missing authentication for critical function vulnerability in @modelcontextprotocol/inspector (npm), affecting versions < 0.14.1. It is fixed in 0.14.1. A critical operation is accessible without requiring any authentication.
- Which versions of @modelcontextprotocol/inspector are affected by CVE-2025-49596? @modelcontextprotocol/inspector (npm) versions < 0.14.1 is affected.
- Is there a fix for CVE-2025-49596? Yes. CVE-2025-49596 is fixed in 0.14.1. Upgrade to this version or later.
- Is CVE-2025-49596 exploitable, and should I be worried? Whether CVE-2025-49596 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-49596 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-49596? Upgrade
@modelcontextprotocol/inspectorto 0.14.1 or later.