{"id":"CVE-2026-59896","aliases":["GHSA-hvrm-45r6-mjfj"],"title":"hono/jsx does not isolate context per request, leading to cross-request data disclosure","summary":"hono/jsx does not isolate context per request, leading to cross-request data disclosure","severity":"medium","cvss":6.5,"cwe":["CWE-362"],"vendor":"hono","product":"hono","ecosystem":"npm","affected":["hono >= 4.11.8, < 4.12.27"],"patched":["hono 4.12.27"],"published":"2026-07-21","updated":"2026-07-21","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-hvrm-45r6-mjfj","references":[{"url":"https://github.com/honojs/hono/security/advisories/GHSA-hvrm-45r6-mjfj"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59896"},{"url":"https://github.com/honojs/hono/commit/fab3b13639339cbd5ba1166a5b23d9ac30c5f64f"},{"url":"https://github.com/honojs/hono/releases/tag/v4.12.27"},{"url":"https://github.com/advisories/GHSA-hvrm-45r6-mjfj"}],"tags":["ghsa","npm"],"epss":0.00299,"epssPercentile":0.22793,"ingestedAt":"2026-07-21T18:53:06.630Z","slug":"CVE-2026-59896","body":"## Overview\n\n### 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\n\n## Affected packages\n\n- `hono >= 4.11.8, < 4.12.27`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `hono 4.12.27`","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}