{"id":"GHSA-46jr-4wx8-v453","revision":"677040376615475b84e4d1661aa281a4","records":[{"revision":"677040376615475b84e4d1661aa281a4","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-46jr-4wx8-v453","aliases":["CVE-2026-111768"],"title":"MCP TypeScript SDK: One HTTP request within the default size limit could exhaust server memory during validation","description":"### Summary\nIn affected versions, servers put no limit on how many array elements and object keys they validated in one request. One HTTP request within the default 4 MiB size limit could exhaust the server's memory, and the process aborted with `JavaScript heap out of memory`.\n\nNo credentials are needed, unless you authenticate requests before they reach the SDK.\n\n### Am I affected?\nYes, if clients you do not fully trust can reach your server over HTTP. The risk is highest for `McpServer` tools whose input contains an array or a record. stdio-only servers are not affected.\n\nAffected versions:\n\n- `@modelcontextprotocol/sdk` 1.3.0 through 1.31.0\n- `@modelcontextprotocol/server` 2.0.0 through 2.2.0\n\n### Fix\nUpgrade to:\n\n- 1.x: `@modelcontextprotocol/sdk` 1.32.0 or later\n- 2.x: `@modelcontextprotocol/server` 2.3.0 or later\n\n**Upgrading alone changes nothing.** The patched versions add an `McpServer` option, `maxToolInputElements`, that is off by default. Make both of these changes:\n\n1. 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.\n2. 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.\n\nIf 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.","state":0,"publishedAt":"2026-10-20T20:06:35+00:00","modifiedAt":"2026-10-20T20:15:05.2220789+00:00","affected":[{"ecosystem":"npm","name":"@modelcontextprotocol/sdk","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"1.3.0"},{"kind":"fixed","version":"1.32.0"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"npm","name":"@modelcontextprotocol/server","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"2.0.0"},{"kind":"fixed","version":"2.3.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"references":["https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-46jr-4wx8-v453","https://github.com/modelcontextprotocol/typescript-sdk/pull/2926","https://github.com/modelcontextprotocol/typescript-sdk/pull/2927","https://github.com/modelcontextprotocol/typescript-sdk/commit/6d8dbc6cb590edf766fcb66b636ca6b654e99c37","https://github.com/modelcontextprotocol/typescript-sdk/commit/fd26801b3b387742fe24a90ed4b275dd6072209f","https://github.com/modelcontextprotocol/typescript-sdk"],"sourceUrl":"https://github.com/advisories/GHSA-46jr-4wx8-v453","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-46jr-4wx8-v453","identifiers":["GHSA-46jr-4wx8-v453","CVE-2026-111768"]},"retained":false,"historicalAffected":[]}],"coverage":[]}