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CVE-2026-52870

MCP Python SDK: Experimental task handlers allow any client to access and cancel other clients' tasks PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
modelcontextprotocol / python-sdkaffected >= 1.23.0, < 1.27.2

CWE

CWE-862

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.