# MCP TypeScript server SDK: Shared transport or server instances delivered one HTTP client's messages to another

Advisory record · `GHSA-jm63-cq47-j5jp`

- **Identifiers:** `GHSA-jm63-cq47-j5jp` · `CVE-2026-111770`
- **State:** Confirmed
- **Severity:** CVSS 7.7 High
- **Critical:** No
- **Weakness (CWE):** [CWE-362](https://cwe.mitre.org/data/definitions/362.html)
- **Tags:** [Race condition](https://agentprime.io/advisories/tag/race-condition.md)
- **Published:** 20 Oct 2026
- **Updated:** 20 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 20 Oct 2026, 20:07 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `@modelcontextprotocol/server` (npm): affected `>=2.0.0, <2.3.0`; fixed in `2.3.0`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.7 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** No score.

## Timeline

- 31 Oct 2026, 13:33 UTC: First seen by agentprime
- 31 Oct 2026, 13:33 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-jm63-cq47-j5jp)
- 5 Nov 2026, 21:28 UTC: [Confirmed by the CVE List](https://www.cve.org/CVERecord?id=CVE-2026-111770)
- 5 Nov 2026, 22:17 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-111770)

## Sources

- [GitHub Advisory Database: GHSA-jm63-cq47-j5jp](https://github.com/advisories/GHSA-jm63-cq47-j5jp)
- [OSV: GHSA-jm63-cq47-j5jp](https://osv.dev/vulnerability/GHSA-jm63-cq47-j5jp)
- <https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-jm63-cq47-j5jp>
- <https://github.com/modelcontextprotocol/typescript-sdk/pull/2918>
- <https://github.com/modelcontextprotocol/typescript-sdk/commit/84804c22e45a662675a198f853b7f00063838a8d>
- <https://github.com/modelcontextprotocol/typescript-sdk>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-jm63-cq47-j5jp>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-jm63-cq47-j5jp/>. Everything for agents: <https://agentprime.io/llms.txt>.