What is CVE-2026-33252?

CVE-2026-33252 is a high-severity vulnerability in Lfprojects Mcp Go Sdk, classified under Cross-Site Request Forgery (CSRF). CVSS score: 7.1/10. Published 2026-03-24.

How severe is CVE-2026-33252?

High severity. CVSS v3 base score is 7.1 out of 10.

CSRF in Lfprojects Mcp Go Sdk

CVE-2026-33252

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.

Vulnerability class: CSRF (Cross-Site Request Forgery)

EPSS: 0.002 (7.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L.

Affected products

Lfprojects Mcp_go_sdk
Modelcontextprotocol Go-sdk — versions < 1.4.1

Weakness classification (CWE)

CWE-352 — Cross-Site Request Forgery (CSRF)

References

security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
security-advisories@github.com (Patch, x_refsource_MISC)

Frequently asked questions

What is CVE-2026-33252?: CVE-2026-33252 is a high-severity vulnerability in Lfprojects Mcp Go Sdk, classified under Cross-Site Request Forgery (CSRF). CVSS score: 7.1/10. Published 2026-03-24.
How severe is CVE-2026-33252?: High severity. CVSS v3 base score is 7.1 out of 10.