CVE-2026-104850 is a high-severity flaw (CVSS 7.5) in the MCP TypeScript SDK: a connected MCP server could name the authorization server that receives your client's stored OAuth credentials. Fixed
Upgrading is not enough for four bundled credential providers. They still follow the server's choice until you pass `expectedIssuer`.
Stdio clients and servers built with the SDK are not affected. If your client may have met an untrusted server, rotate the client secret or signing key and revoke its tokens.