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CVE-2026-33252 Detail

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.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/modelcontextprotocol/go-sdk/commit/a433a831d6e5d5ac3b9e625a8095aa8eaa040dfc GitHub, Inc.
https://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-89xv-2j6f-qhc8 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-352 Cross-Site Request Forgery (CSRF) GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-33252
NVD Published Date:
03/23/2026
NVD Last Modified:
03/24/2026
Source:
GitHub, Inc.