{"id":"CVE-2026-59896","aliases":["GHSA-hvrm-45r6-mjfj"],"url":"https://o3.security/vulnerability/CVE-2026-59896","summary":"hono/jsx does not isolate context per request, leading to cross-request data disclosure","details":"### Summary\n\n`hono/jsx` did not isolate context values per request during server-side rendering. While an async component was suspended on `await`, its provided context value stayed observable to other requests rendering concurrently, so `useContext()` could return a value from a different in-flight request.\n\n### Details\n\nDuring server-side rendering, context values were kept in a process-wide structure rather than scoped to each request's render. While an async component awaited, another request entering the same provider could observe or replace the value; when the first render resumed, it could read the other request's context.\n\nThis affects the usual ways request-scoped data is passed through a server-rendered JSX tree:\n\n- `createContext()` / `useContext()`\n- the `jsxRenderer` middleware and `useRequestContext()`\n\nIt arises only when context is read after an `await` inside an async component while requests render concurrently. Reading context synchronously (before any `await`), purely synchronous rendering, and client-side (DOM) rendering are not affected.\n\n### Impact\n\nUnder concurrent requests, a response could be rendered with another request's context. A user may receive HTML rendered for a different user, and an authorization check performed after an `await` may be evaluated against another user's data.\n\nThis may lead to:\n\n- disclosure of rendered output intended for another user\n- authorization decisions made with the wrong request's context\n- cross-request mixing of session or other request-scoped state","published":"2026-07-08T16:08:07.975Z","modified":"2026-08-12T03:51:29.140281282Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N"},"epss":{"score":0.00299,"percentile":0.22579,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"hono","fixedVersion":"4.12.27"}],"fix":{"url":"https://github.com/honojs/hono/commit/fab3b13639339cbd5ba1166a5b23d9ac30c5f64f","label":"honojs/hono@fab3b13"},"references":[{"type":"WEB","url":"https://github.com/honojs/hono/releases/tag/v4.12.27"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59896.json"},{"type":"ADVISORY","url":"https://github.com/honojs/hono/security/advisories/GHSA-hvrm-45r6-mjfj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59896"},{"type":"FIX","url":"https://github.com/honojs/hono/commit/fab3b13639339cbd5ba1166a5b23d9ac30c5f64f"},{"type":"PACKAGE","url":"https://github.com/honojs/hono"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:29.140281282Z"}}