MCP TypeScript SDK: Experimental tasks were not tied to the session that created them
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.
What to do
Upgrade to @modelcontextprotocol/sdk 1.32.0 or later. Alternatively, remove taskStore or create one InMemoryTaskStore per session.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @modelcontextprotocol/sdk | >= 1.24.0, < 1.32.0 | 1.32.0 |
References
- https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-22jm-h49p-29qw
- https://github.com/modelcontextprotocol/typescript-sdk/pull/2925
- https://github.com/modelcontextprotocol/typescript-sdk/commit/727075b5bbeb77fbea22041b36b72a73042160fa
- https://github.com/modelcontextprotocol/typescript-sdk
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L- Weakness (CWE)
CWE-639, CWE-862- Platform
- npm
- Package
@modelcontextprotocol/sdk- Disclosed
- 20.10.2026
- Updated
- 20.10.2026 21:38
Sources and licenses · Edited or translated by DockRay; source rights and applicable licenses are retained.
OSV / GitHub Advisory Database - GHSA-22jm-h49p-29qw - CC BY 4.0
Vulnerability history: @modelcontextprotocol/sdk
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 8
- First → latest
- 12.2025 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 6
- Medium 2
Disclosures per year
- 2025: 1
- 2026: 7
-
MCP TypeScript SDK: Experimental tasks were not tied to the session that created them this entry
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