CVE-2025-49596: MCP Inspector Package Lacks Authentication Leading to Remote Code Execution
Summary
CVE-2025-49596: MCP Inspector proxy server lacks authentication between the Inspector client and proxy. Affects @modelcontextprotocol/inspector versions < 0.14.1. Fixed in 0.14.1. How to fix ↓
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Background
The MCP Inspector is a tool designed for managing and monitoring model contexts in applications. It facilitates the execution of commands and provides insights into the state of the models. However, versions prior to 0.14.1 are vulnerable due to a lack of authentication between the Inspector client and its proxy server, which can lead to unauthorized access and command execution.
Vulnerability Detail
The vulnerability arises from the absence of authentication mechanisms between the MCP Inspector client and the proxy server. This flaw allows attackers to send unauthenticated requests, potentially executing arbitrary MCP commands over standard input/output. The implications of this vulnerability are severe, as it could lead to remote code execution, compromising the integrity and security of the system.
How To Fix
Latest published version: 2.12.0 as of 23 Oct 2026
npm install @modelcontextprotocol/inspector@2.12.0Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
0.14.1
This is the first release that contains the fix.
npm install @modelcontextprotocol/inspector@0.14.1Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, there are no specific workarounds available to mitigate this vulnerability without upgrading to the patched version. It is strongly recommended to update the package as soon as possible.
Conclusion
The MCP Inspector vulnerability (CVE-2025-49596) poses a critical risk due to the lack of authentication between the client and proxy server, allowing for potential remote code execution. Users are urged to upgrade to version 0.14.1 or later to secure their applications.
See every vulnerability recorded for @modelcontextprotocol/inspector →
FAQ
The MCP Inspector is a tool used for managing and monitoring model contexts in applications, allowing users to execute commands and gain insights into model states.
Versions of MCP Inspector prior to 0.14.1 are vulnerable to this issue.
This vulnerability can enable remote code execution, allowing attackers to execute arbitrary commands on the server without authentication.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in real-time. Visit Vulert Scanner to check if your application is affected without any signup.
There are no effective workarounds available. The only solution is to upgrade to version 0.14.1 or later.
References
Related vulnerabilities
Recent vulnerabilities recorded for @modelcontextprotocol/inspector.
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