What is CVE-2026-52870?

CVE-2026-52870 is a high-severity vulnerability in Modelcontextprotocol Python-sdk, classified under Missing Authorization. CVSS score: 7.6/10. Published 2026-07-15.

How severe is CVE-2026-52870?

High severity. CVSS v3 base score is 7.6 out of 10.

Auth bypass in Modelcontextprotocol Python-sdk

CVE-2026-52870

The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). From 1.23.0 until 1.27.2, default handlers installed by server.experimental.enable_tasks() for tasks/list, tasks/get, tasks/result, and…

Vulnerability class: Broken Access Control

CVSS v3 metric

CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L.

Affected products

Modelcontextprotocol Python-sdk — versions >= 1.23.0, < 1.27.2

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

security-advisories@github.com (x_refsource_MISC)
security-advisories@github.com (x_refsource_MISC)
security-advisories@github.com (x_refsource_MISC)
security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-52870?: CVE-2026-52870 is a high-severity vulnerability in Modelcontextprotocol Python-sdk, classified under Missing Authorization. CVSS score: 7.6/10. Published 2026-07-15.
How severe is CVE-2026-52870?: High severity. CVSS v3 base score is 7.6 out of 10.