high · 8.6 Patched

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

CVE-2026-111767 · GHSA-22jm-h49p-29qw · published 20 Oct 2026

How serious is it

  • Severity: high, CVSS score 8.6 out of 10.
  • No exploit prediction (EPSS) score yet.
  • Not on the CISA list of exploited vulnerabilities.
  • No public exploit in Exploit-DB.

Is your app affected by CVE-2026-111767?

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Who is affected

  • @modelcontextprotocol/sdk (npm) >= 1.24.0, < 1.32.0

How to check

  1. Run npm ls @modelcontextprotocol/sdk in your project to see the installed version, including copies pulled in by other packages.
  2. Or paste your lockfile into the checker: it lists every package with a known vulnerability, this one included.
  3. Or run npx shippable-dev scan localhost:3000 in your project folder. It reads your lockfile and flags this vulnerability along with every other known one.

How to fix

Copies a prompt for Claude Code, Cursor or Codex: it checks your lockfiles for this and upgrades it.
  1. Upgrade @modelcontextprotocol/sdk to 1.32.0 or later, commit the lockfile and redeploy.
  2. If a vulnerable version was live, check your logs and rotate the secrets that server could read.

The advisory

### 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.

Check your whole app

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References

Merged from GitHub Advisory Database. Last updated 23 Oct 2026. All vulnerabilities · RSS · JSON

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