CVE-2026-33252
Go MCP SDK
7.1
- Severity
- High
- Published
- March 24, 2026
- Last modified
- June 17, 2026
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 or sessionless configurations, this allows an arbitrary website to send MCP requests to a local server and potentially trigger tool execution. Version 1.4.1 contains a patch for the issue.
CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L
Weakness
- CWE-352 Cross-site request forgery
References
- github.comPatch
- github.comPatchVendor Advisory