Description

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.

INFO

Published Date :

2026-03-23T23:44:16.106Z

Last Modified :

2026-03-24T18:39:50.841Z

Source :

GitHub_M
AFFECTED PRODUCTS

The following products are affected by CVE-2026-33252 vulnerability.

Vendors Products
Modelcontextprotocol
  • Go-sdk
REFERENCES

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-33252.

URL Resource
https://github.com/modelcontextprotocol/go-sdk/commit/a433a831d6e5d5ac3b9e625a8095aa8eaa040dfc cve-icon cve-icon cve-icon
https://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-89xv-2j6f-qhc8 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-33252 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-33252 cve-icon
Login to claim this CVE

CVSS Vulnerability Scoring System

Detailed values of each vector for above chart.
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact