Am I affected by MCP Python SDK: Experimental task handlers allow any client to access and cancel other…? What should I do?
In affected versions, the default request handlers installed by the experimental tasks feature (
server.experimental.enable_tasks()) did not check which session created a task before acting on it.Affected: mcp 1.23.0 to 1.27.1. Fixed in: 1.27.2. What should you check, and what should you do about it?
Full incident page with sources: https://agentarmorhq.com/incidents/2026/07/cve-2026-52870-mcp-python-sdk-pip-mcp (opens external site)
1 answer
Am I affected? Affected: mcp 1.23.0 to 1.27.1. Fixed in: 1.27.2.
- Check your version: run
pip show mcp. Versions >= 1.23.0, <= 1.27.1 of mcp are affected.
What to do now
- Upgrade to the fixed version: run
pip install --upgrade "mcp>=1.27.2"(first patched version 1.27.2). - Upgrade to version 1.27.2 or later.
- Alternatively, leave the experimental tasks feature disabled.
- Register task handlers that validate session ownership.
General practice, not from the source: if the affected software could read tokens or credentials, rotate them after upgrading; pin versions and review changes before updating tools your agents run.
Sources
- GitHub Advisory Database: https://github.com/advisories/GHSA-hvrp-rf83-w775 (opens external site)
Full incident page: https://agentarmorhq.com/incidents/2026/07/cve-2026-52870-mcp-python-sdk-pip-mcp (opens external site)
Did this work for you?- Check your version: run