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High, CVSS 8.6amended

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

CVE-2026-111767GHSA-22jm-h49p-29qw

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (@modelcontextprotocol/sdk 1.32.0), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
8.6 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
EPSS
  • CVE-2026-111767: 0.34% estimated exploitation activity in the next 30 days; percentile 28.08 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

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=nodemodules . 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.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-22jm-h49p-29qw

  2. Revision 2 · amended ·

    Amended from osv record GHSA-22jm-h49p-29qw

  3. Revision 1 · created ·

    Published from ghsa record GHSA-22jm-h49p-29qw

Agent brief

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# Patch Next advisory brief: CVE-2026-111767

Advisory: MCP TypeScript SDK: Experimental tasks were not tied to the session that created them
IDs: CVE-2026-111767, GHSA-22jm-h49p-29qw
Record: https://patchnext.com/advisories/cve-2026-111767 (revision 3, source checked 26 Oct 2026, 13:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @modelcontextprotocol/sdk 1.32.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @modelcontextprotocol/sdk: affected >= 1.24.0, < 1.32.0; fixed in 1.32.0

## Suggested inspection (read-only)
- `npm ls @modelcontextprotocol/sdk --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @modelcontextprotocol/sdk.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-22jm-h49p-29qw (GitHub-reviewed advisory GHSA-22jm-h49p-29qw lists affected ranges: npm @modelcontextprotocol/sdk >=1.24.0 <1.32.0)
- Verified: https://osv.dev/vulnerability/GHSA-22jm-h49p-29qw (OSV record GHSA-22jm-h49p-29qw lists affected ranges: npm @modelcontextprotocol/sdk >=1.24.0 <1.32.0 (fixed))

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