Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Lfprojects | Mcp Python Sdk | >= 1.23.0, < 1.27.2 |
Related Weaknesses (CWE)
References
- https://github.com/modelcontextprotocol/python-sdk/commit/62137874ff26dd74d2fea8Patch
- https://github.com/modelcontextprotocol/python-sdk/pull/2720Issue TrackingPatch
- https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2Release Notes
- https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-hvrpVendor Advisory
FAQ
What is CVE-2026-52870?
CVE-2026-52870 is a vulnerability with a CVSS score of 7.6 (HIGH). 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 t...
How severe is CVE-2026-52870?
CVE-2026-52870 has been rated HIGH with a CVSS base score of 7.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-52870?
Check the references section above for vendor advisories and patch information. Affected products include: Lfprojects Mcp Python Sdk.