# AN-2026-0063: MCP TypeScript SDK: HTTP server transports and handlers did not limit request body size or JSON-RPC batch length (GHSA-f897-62hf-6gxq)

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- id: AN-2026-0063 (version 2; cite https://breakwire.org/claim/AN-2026-0063/v/2)
- kind: advisory · status: active · review: editor
- source: <https://github.com/advisories/GHSA-f897-62hf-6gxq>
- more sources: <https://api.github.com/advisories/GHSA-f897-62hf-6gxq>
- event date: 2026-10-27
- services: mcp, mcp-typescript-sdk
- affected: npm:@modelcontextprotocol/sdk >= 1.10.0, < 1.30.1; npm:@modelcontextprotocol/server >= 2.0.0, < 2.1.0; npm:@modelcontextprotocol/node >= 2.0.0, < 2.1.0; npm:@modelcontextprotocol/hono >= 2.0.0, < 2.0.1
- fixed in: @modelcontextprotocol/sdk 1.30.1; @modelcontextprotocol/server 2.1.0; @modelcontextprotocol/node 2.1.0; @modelcontextprotocol/hono 2.0.1
- severity: high
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 10, fixed 0, not fixed 0

## Summary
```text
### 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.
```

## Statements (checkable)
0. GHSA-f897-62hf-6gxq: MCP TypeScript SDK: HTTP server transports and handlers did not limit request body size or JSON-RPC batch length  [✓0 ✗0]
1. Affected: npm:@modelcontextprotocol/sdk >= 1.10.0, < 1.30.1; npm:@modelcontextprotocol/server >= 2.0.0, < 2.1.0; npm:@modelcontextprotocol/node >= 2.0.0, < 2.1.0; npm:@modelcontextprotocol/hono >= 2.0.0, < 2.0.1  [✓0 ✗0]
2. Patched: @modelcontextprotocol/sdk 1.30.1; @modelcontextprotocol/server 2.1.0; @modelcontextprotocol/node 2.1.0; @modelcontextprotocol/hono 2.0.1  [✓0 ✗0]
3. Am I affected (advisory text): 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. No credentials were needed unless the application authenticates requests before they reach the SDK.  [✓0 ✗0]

## Fix
```text
Exposure first: only servers that clients you do not fully trust can reach over Streamable HTTP are affected; stdio-only servers are not. If exposed, upgrade to a patched version: @modelcontextprotocol/sdk 1.30.1; @modelcontextprotocol/server 2.1.0; @modelcontextprotocol/node 2.1.0; @modelcontextprotocol/hono 2.0.1 (bodies over 4 MiB then get 413, batches over 100 messages 400; raise maxRequestBodySize if needed). If you cannot upgrade yet, cap request body size in a reverse proxy.
```

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0063/reports_

## History
- v2 2026-10-29 by wire-editor: 0.11.0 audit: deployment condition (Streamable HTTP reachable by untrusted clients vs stdio-only) from the advisory's Am I affected section; fix leads with exposure (changed statements, fix, conditions)
- v1 2026-10-28 by wire-editor: filed from primary source opened 2026-10-28