Packages / @modelcontextprotocol/sdk / Security

HighVulnerabilityGHSA-22jm-h49p-29qwCVE-2026-111767Published 20 Oct 2026

MCP TypeScript SDK: Experimental tasks were not tied to the session that created them

Affected releases · @modelcontextprotocol/sdk

  • 1.x1.24.0 – 1.31.0Fixed in 1.32.0

On 1.x, the newest line:

npm install @modelcontextprotocol/sdk@1.32.0

  1. Not affected

    0.4.0 – 1.23.1

    64 releases

  2. Affected

    1.24.0 – 1.31.0

    16 releases

  3. Fixed

    1.32.0 – 1.32.1

    2 releases, latest

82 stable releases of @modelcontextprotocol/sdk, oldest to newest.

Is your project affected?

Paste your package.json, or type the range you declare for @modelcontextprotocol/sdk. It is read in your browser and sent nowhere.

What happens

Summary

In affected versions, the experimental tasks feature (taskStore) did not check which session created a task. Clients sharing one InMemoryTaskStore could list, read and cancel each other's tasks.

Experimental tasks are deprecated. The 2026-07-28 specification replaced them with a redesigned extension. The best course of action is to stop using them.

Am I affected?

Only if your HTTP server passes taskStore to McpServer or Server. If grep -ri taskstore --exclude-dir=node_modules . finds nothing, you are not affected.

Affected versions: @modelcontextprotocol/sdk 1.24.0 through 1.31.0. The 2.x packages are not affected.

Fix

Upgrade to @modelcontextprotocol/sdk 1.32.0 or later. Each task is now tied to the session that created it, so a client that starts a new session can no longer reach its earlier tasks.

If you cannot upgrade yet, remove taskStore, or create one InMemoryTaskStore per session.