{"id":"GHSA-49rj-9fvp-4h2h","summary":"React Router's vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE","details":"When using React Router v7 in [Framework Mode](https://reactrouter.com/start/modes#framework), there exists a combination of steps that could potentially allow unauthorized RCE through external requests.  This first requires the application code to have an existing prototype pollution vulnerability.  This can be leveraged into a 2-step attack in which the second step can trigger unauthorized RCE on the remote server.\n\n\u003e [!NOTE]\n\u003e This does not impact your React Router application if you are using [Declarative Mode](https://reactrouter.com/start/modes#declarative) (`\u003cBrowserRouter\u003e`) or [Data Mode](https://reactrouter.com/start/modes#data) (`createBrowserRouter`/`\u003cRouterProvider\u003e`).","aliases":["CVE-2026-42211"],"modified":"2026-07-17T21:13:19.374524429Z","published":"2026-06-03T21:03:32Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-06-03T21:03:32Z","nvd_published_at":"2026-06-02T20:16:36Z","cwe_ids":["CWE-502"]},"references":[{"type":"WEB","url":"https://github.com/remix-run/react-router/security/advisories/GHSA-49rj-9fvp-4h2h"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42211"},{"type":"PACKAGE","url":"https://github.com/remix-run/react-router"}],"affected":[{"package":{"name":"react-router","ecosystem":"npm","purl":"pkg:npm/react-router"},"ranges":[{"type":"SEMVER","events":[{"introduced":"7.0.0"},{"fixed":"7.14.2"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 7.14.1","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-49rj-9fvp-4h2h/GHSA-49rj-9fvp-4h2h.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}