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)

Published · last modified .

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.

EPSS exploit prediction

EPSS: 0.002 (10.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-33252: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

References

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.