AIKIDO-2026-632017
@modelcontextprotocol/inspector-server is vulnerable to Server-Side Request Forgery (SSRF)
61
Medium Risk
This Affects:
@modelcontextprotocol/inspector-serverTL;DR
The Inspector's server-side /fetch proxy forwards client-supplied http/https URLs to fetch() without restricting the target address. A connected MCP server can advertise OAuth discovery or token endpoints that resolve to link-local or cloud-metadata addresses such as 169.254.169.254, causing the proxy to request them and return the response. When the proxy runs on a cloud host this can expose instance metadata and IAM credentials, and redirects from an allowed host into a blocked address were not re-validated. The fix resolves the target host, blocks link-local/cloud-metadata ranges including IPv4-mapped IPv6 forms, and re-validates every redirect hop, returning 403 for blocked targets.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and you run the Inspector proxy where it can reach internal or cloud-metadata addresses and connect it to an untrusted MCP server.
Background info
@modelcontextprotocol/inspector-server is vulnerable to Server-Side Request Forgery (SSRF) in versions 0.21.2 - 0.22.0.
How to fix this
Upgrade the @modelcontextprotocol/inspector-server and/or the @modelcontextprotocol/inspector library to the patch version.
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SOC 2Compliant
ISO 27001Compliant