Permalink
CVE-2026-33252
7.1 HIGH
- CVSS version: 3.1
- Attack vector (AV): NETWORK
- Attack complexity (AC): LOW
- Privileges required (PR): NONE
- User interaction (UI): REQUIRED
- Scope (S): UNCHANGED
- Confidentiality impact (C): NONE
- Integrity impact (I): HIGH
- Availability impact (A): LOW
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 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.
References
Affected products
go-sdk
- ==< 1.4.1
Package maintainers
-
@lufia Kyohei Kadota <lufia@lufia.org>