Release 1.0.3 · modelcontextprotocol/inspector

What's Changed

1.0.3 is a security release for the deprecated v1 line. Upgrade with npx @modelcontextprotocol/inspector@v1-latest, or move to v2 (@latest).

Proxy rejects browser requests without an allowed Origin when authentication is disabled, and DANGEROUSLY_OMIT_AUTH is read strictly (only true, 1 or yes) (GHSA-wmjf-2m46-2352)
The OAuth callback no longer takes connection settings from its URL. It reconnects only with the connection saved in that tab before the redirect, and never over stdio (GHSA-4fc4-wcmh-4g86)
MCP App links open with noopener,noreferrer and only for http(s) URLs, and the proxy rejects same-origin browser requests to its API. A new DANGEROUSLY_ALLOW_SAME_ORIGIN_API opt-out covers single-origin reverse-proxy setups (GHSA-6x67-4w4w-9f3w)
The stored proxy token is no longer sent to a proxy address supplied in the URL, and a query-supplied address is no longer saved. MCP_PROXY_PORT must be a number (GHSA-2rq8-f55p-j2jp)
The /fetch proxy drops Authorization, Cookie and related headers on cross-origin redirects, and refuses a cross-origin redirect of a request that still carries a body (GHSA-f6mc-jg3x-vq53)
The /fetch proxy caps upstream response bodies at 5 MiB (GHSA-m5pj-3536-3xcp)
SSE connection logs show header names, not values, and stdio env values are masked in the query log (GHSA-8qgq-27v6-55w3)
chore: bump version to 1.0.3 by @cliffhall in #2754

DANGEROUSLY_ALLOW_SAME_ORIGIN_API: off by default. Set it to true, 1 or yes only if the client and proxy are served from one origin behind a reverse proxy. See the README's "Same-origin API Requests" section.

This release addresses vulnerabilities reported by these community members. Thank you for taking the time to report them responsibly:

Full Changelog: 1.0.2...1.0.3
Smoke test ledger: https://claude.ai/artifact/5dXSVLSAQux1LxY2BosADa