MCP Go SDK Allows Cross-Site Tool Execution for HTTP Servers without Authorizatrion
The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.1, the Go SDK's Streamable HTTP transport accepted browser-generated cross-site `POST` requests without validating the `Origin` header and without requiring `Content-Type: application/json`. In deployments without Authorization, especially stateless …
Severity high: primary CNA CVSS 7.1 v3.1 (worst CNA-provided scenario) Not listed in this KEV snapshot. Forecast present in this snapshot.
Published 2026-03-23T23:44:16.106Z. Updated 2026-03-24T18:39:50.841Z.