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

Date Oct 20, 2026

Type Vendor advisory

Signal High-risk advisory

Vendor / Product npm · @modelcontextprotocol/server

CVE CVE-2026-111770

High-risk advisory CVE-2026-111770

Summary

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

Why it matters

GitHub has published a reviewed security advisory for @modelcontextprotocol/server. Prioritize it with other application dependency updates.

Operator check

Check whether @modelcontextprotocol/server is present in application dependency manifests, lockfiles, or build images. Review the GitHub advisory and upgrade to a patched version where available.

Sources

GitHub Advisory GHSA-jm63-cq47-j5jp NVD — CVE-2026-111770 Source reference

PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.

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