CVE-2026-111768

MCP TypeScript SDK: One HTTP request within the default size limit could exhaust server memory during validation

The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.

CVE-2026-111768 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.32.0, 2.3.0); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

Upgrade to:

• 1.x: @modelcontextprotocol/sdk 1.32.0 or later
• 2.x: @modelcontextprotocol/server 2.3.0 or later

Upgrading alone changes nothing. The patched versions add an McpServer option, maxToolInputElements, that is off by default. Make both of these changes:

1. Set maxToolInputElements just above the largest input your tools need, for example new McpServer(info, { maxToolInputElements: 10_000 }). It counts array elements and object keys in a call's arguments. A call over the limit gets an isError: true result.
2. Lower the request size limit to what your tools need. The option covers tool arguments only, and the size limit covers everything else. Set maxRequestBodySize on the transport or createMcpHandler(). If you parse the body yourself, for example with express.json() or Fastify, set that parser's limit.

If you cannot upgrade yet, make the second change. maxRequestBodySize needs @modelcontextprotocol/sdk 1.30.1 or @modelcontextprotocol/server 2.1.0. Below that, use a reverse proxy.

1. What is CVE-2026-111768? CVE-2026-111768 is a high-severity allocation of resources without limits or throttling vulnerability in @modelcontextprotocol/sdk (npm), affecting versions >= 1.3.0, < 1.32.0. It is fixed in 1.32.0, 2.3.0. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
2. How severe is CVE-2026-111768? CVE-2026-111768 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2026-111768?
   • @modelcontextprotocol/sdk (npm) (versions >= 1.3.0, < 1.32.0)
   • @modelcontextprotocol/server (npm) (versions >= 2.0.0, < 2.3.0)
4. Is there a fix for CVE-2026-111768? Yes. CVE-2026-111768 is fixed in 1.32.0, 2.3.0. Upgrade to this version or later.
5. Is CVE-2026-111768 exploitable, and should I be worried? Whether CVE-2026-111768 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-111768 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-111768?
   • Upgrade @modelcontextprotocol/sdk to 1.32.0 or later
   • Upgrade @modelcontextprotocol/server to 2.3.0 or later

Other vulnerabilities in @modelcontextprotocol/sdk