OAuth Vulnerability in MCP TypeScript SDK Affecting Model Context Protocol Servers
CVE-2026-104850
What is CVE-2026-104850?
The MCP TypeScript SDK facilitates communication with Model Context Protocol servers and clients. However, versions prior to 1.31.0 and 2.2.0 contain a vulnerability whereby an MCP server can influence the OAuth authorization server that receives client credentials. Malicious entities could potentially compromise the client's OAuth tokens by naming their own authorization server, leading to unauthorized access without user action. Applications utilizing this SDK over HTTP with specific authentication providers are particularly at risk. Users are encouraged to upgrade to the patched versions, or, if upgrading is not feasible, to restrict connections to trusted MCP servers.
Affected Version(s)
typescript-sdk >= 1.12.0, < 1.31.0 < 1.12.0, 1.31.0
typescript-sdk >= 2.0.0, < 2.2.0 < 2.0.0, 2.2.0