GHSA-f897-62hf-6gxq

Suggest an improvement
Source
https://github.com/advisories/GHSA-f897-62hf-6gxq
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-f897-62hf-6gxq/GHSA-f897-62hf-6gxq.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-f897-62hf-6gxq
Published
2026-10-27T19:02:00Z
Modified
2026-10-27T19:15:22Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
MCP TypeScript SDK: HTTP server transports and handlers did not limit request body size or JSON-RPC batch length
Details

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.

Database specific 
{
    "cwe_ids":  [
        "CWE-770"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-10-27T19:02:00Z",
    "nvd_published_at":  null,
    "severity":  "HIGH"
}
References

Affected packages

npm
@modelcontextprotocol/sdk

Package

Name
@modelcontextprotocol/sdk
View open source insights on deps.dev
Purl
pkg:npm/%40modelcontextprotocol/sdk

Affected ranges

Type
SEMVER
Events
Introduced
1.10.0
Fixed
1.30.1

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-f897-62hf-6gxq/GHSA-f897-62hf-6gxq.json"
@modelcontextprotocol/server

Package

Name
@modelcontextprotocol/server
View open source insights on deps.dev
Purl
pkg:npm/%40modelcontextprotocol/server

Affected ranges

Type
SEMVER
Events
Introduced
2.0.0
Fixed
2.1.0

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-f897-62hf-6gxq/GHSA-f897-62hf-6gxq.json"
@modelcontextprotocol/node

Package

Name
@modelcontextprotocol/node
View open source insights on deps.dev
Purl
pkg:npm/%40modelcontextprotocol/node

Affected ranges

Type
SEMVER
Events
Introduced
2.0.0
Fixed
2.1.0

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-f897-62hf-6gxq/GHSA-f897-62hf-6gxq.json"
@modelcontextprotocol/hono

Package

Name
@modelcontextprotocol/hono
View open source insights on deps.dev
Purl
pkg:npm/%40modelcontextprotocol/hono

Affected ranges

Type
SEMVER
Events
Introduced
2.0.0
Fixed
2.0.1

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-f897-62hf-6gxq/GHSA-f897-62hf-6gxq.json"