CVE-2026-52870: MCP Python SDK experimental task handlers allow unauthorized task access

# CVE-2026-52870: MCP Python SDK experimental task handlers allow unauthorized task access

https://gcdradar.vercel.app/incidents/cve-2026-52870-mcp-python-sdk-experimental-task-handlers-all · AIR-2026-0805 · closed 2026-07-15

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2026-07-15 (happened 2026-07-16)
- AI role: Attack on AI
- Products: MCP Python SDK
- CVE ids: CVE-2026-52870
- CVSS: 7.6

## Summary

An authorization vulnerability in the MCP Python SDK experimental tasks feature allows connected clients to observe, read results from, and cancel tasks belonging to other clients. A patch has been issued for affected library versions.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Latest updates

- 2026-07-16: CVE-2026-52870: MCP Python SDK: Experimental task handlers allow any client to access and cancel other clients' tasks (https://github.com/advisories/GHSA-hvrp-rf83-w775)
- 2026-07-15: CVE-2026-52870: The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). (https://nvd.nist.gov/vuln/detail/CVE-2026-52870)

## Sources

- 2026-07-15 NVD: CVE-2026-52870: The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). https://nvd.nist.gov/vuln/detail/CVE-2026-52870
- 2026-07-16 GitHub Advisory Database: CVE-2026-52870: MCP Python SDK: Experimental task handlers allow any client to access and cancel other clients' tasks https://github.com/advisories/GHSA-hvrp-rf83-w775

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.