What is CVE-2025-66416?

CVE-2025-66416 is a high-severity vulnerability in Lfprojects Mcp_python_sdk, classified under Initialization of a Resource with an Insecure Default. CVSS score: 8.1/10. Published 2025-12-02.

How severe is CVE-2025-66416?

High severity. CVSS v3 base score is 8.1 out of 10.

RCE in Lfprojects Mcp_python_sdk

CVE-2025-66416

The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.23.0, tThe Model Context Protocol (MCP) Python SDK does not enable DNS rebinding protection by default for HTTP-ba…

EPSS: 0.005 (37.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.

Affected products

Lfprojects Mcp_python_sdk
Modelcontextprotocol Python-sdk — versions < 1.23.0

Weakness classification (CWE)

CWE-1188 — Initialization of a Resource with an Insecure Default

References

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

Frequently asked questions

What is CVE-2025-66416?: CVE-2025-66416 is a high-severity vulnerability in Lfprojects Mcp_python_sdk, classified under Initialization of a Resource with an Insecure Default. CVSS score: 8.1/10. Published 2025-12-02.
How severe is CVE-2025-66416?: High severity. CVSS v3 base score is 8.1 out of 10.