Disclosed weakness · no CVE recorded

MCP TypeScript HTTP servers lack request-body and batch limits

Model Context Protocol · TypeScript SDK HTTP server packages

First documented disclosure · Review checkpoint

Summary

Oversized bodies or long JSON-RPC batches can exhaust resources or block other clients.

Severity and exploitation evidence

High · 7.5/10 · CVSS 3.1. Severity source.

Exploitation not established: The maintainer advisory establishes a weakness, not observed malicious exploitation. No CVE is assigned on the reviewed advisory.

Exploitation evidence source

Technical severity is not a measure of observed attacks or of risk to your deployment. Attempts, demonstrations, and successful compromise retain the qualifications in the source.

How the weakness works

HTTP transports do not bound request bodies or batch-message counts.

Conditions required

Untrusted clients can reach Streamable HTTP; no credentials unless the application authenticates before SDK handling. Stdio-only servers are unaffected.

Potential impact

Memory exhaustion and denial of service.

Affected versions and configurations

@modelcontextprotocol/sdk >=1.10.0, <1.30.1; server and node >=2.0.0, <2.1.0; hono >=2.0.0, <2.0.1.

Fix and mitigation status

sdk 1.30.1; server/node 2.1.0; hono 2.0.1. Upgrade each installed affected package.

Practical next steps

Upgrade all affected packages. New defaults reject bodies over 4 MiB and batches over 100 messages; interim proxy body limits do not by themselves cap batch length.

Operating lesson

Bound both request size and the work one request can trigger.

Evidence and limits

GHSA-f897-62hf-6gxq was published October 15; October 27 aggregator ingestion does not reset disclosure. The maintainer lists no known CVE. It is distinct from Python SDK CVE-2026-116685 and from separate TypeScript validation-memory advisories.

Sources