CVE-2026-71850

Hono: `memo()` retains SSR output across requests, leading to cross-user data disclosure

State
Published
Severity
4.8 Medium
Published
Aug 7, 2026
Updated
Aug 10, 2026
Reserved
Aug 7, 2026

Read the record on cve.org

Description

Hono is a Web application framework that provides support for any JavaScript runtime. From 3.8.0 to 4.12.33, memo() from hono/jsx retains the result of a server side render and reuses it for later renders with comparator equal props, and request scoped values read inside the component take no part in that comparison, so a response can contain HTML rendered for another user's request. Components wrapped with memo() are compared by props alone; values read implicitly during rendering, such as JSX Context through createContext() and useContext(), useRequestContext() from hono/jsx-renderer, and getContext() from hono/context-storage, do not participate, and the retained result lives as long as the wrapped component, so it outlives the request that produced it. A user may receive a response containing HTML rendered for another user when both render the same memoized component with comparator equal props on the same warm instance, which may disclose another user's account or profile data, disclose request scoped secrets embedded in HTML such as CSRF tokens, or expose role specific content to users who should not receive it. This issue is fixed in version 4.12.34.

Scores

CVSSScoreVectorSource
3.14.8 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:NGitHub_M

Weaknesses

  • CWE-488 Exposure of Data Element to Wrong Session

Affected Products

ProductVersions
honohonojs
  • >= 3.8.0, < 4.12.34Affected

References

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