## Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies

- 種別: advisory
- 重大度: medium
- 関連技術: python
- CVE: CVE-2026-116685
- 公開日時: 2026-10-27T21:05:34.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-5h93-6whr-6q8j)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-5h93-6whr-6q8j

影響: pip:mcp >= 2.0.0, < 2.2.0 → 2.2.0, pip:mcp >= 1.8.0, < 1.30.0 → 1.30.0
In affected versions, the SDK's Streamable HTTP and SSE client transports followed HTTP redirects to any host. If the configured MCP endpoint answered with a redirect to a different origin: - custom headers set on the client (for example an X-API-Key credential) were sent to that origin, and - on a 307 or 308 redirect the request body was re-sent there too. The SDK's OAuth client providers followed redirects on their own discovery, registration and token requests in the same way. A lone Authori…