CVE-2026-52870

high

Description

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 tasks/cancel operate only on task identifiers without recording the session that created each task, allowing any connected client to enumerate, read results from, consume messages for, or cancel other clients' tasks. This issue is fixed in version 1.27.2.

References

https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-hvrp-rf83-w775

https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2

https://github.com/modelcontextprotocol/python-sdk/pull/2720

https://github.com/modelcontextprotocol/python-sdk/commit/62137874ff26dd74d2fea80ff528a7fd9ca7a5e7

Details

Source: Mitre, NVD

Published: 2026-07-15

Updated: 2026-07-16

Risk Information

CVSS v2

Base Score: 8

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:P/A:P

Severity: High

CVSS v3

Base Score: 7.6

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L

Severity: High

EPSS

EPSS: 0.00043