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

- 種別: advisory
- 重大度: high
- 関連技術: nodejs
- CVE: CVE-2026-111770
- 公開日時: 2026-10-20T20:07:29.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-jm63-cq47-j5jp)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-jm63-cq47-j5jp

影響: npm:@modelcontextprotocol/server >= 2.0.0, < 2.3.0 → 2.3.0
Summary In affected versions, an MCP server reached over HTTP could deliver one client's responses and notifications to another client. This happened when clients shared one stateless transport, or one McpServer or Server instance. Messages were matched to a connection by JSON-RPC id alone. SDK clients number requests from 0, so ids collide in normal use. Am I affected? Yes, if more than one client can reach your HTTP endpoint and your code creates the transport or the server once at startup, i…