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MEDIUM

CVE-2026-71850

CVE-2026-71850 — Hono: `memo()` retains SSR output across requests, leading to cross-user data disclosure

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…

Published Updated Sources: cvelistV5, GitHub_M

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

0%

chance of exploitation in 30 days

Affects

honojs

hono

CVSS base

4.8

MEDIUM

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

No

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

honojs

Products (1)

hono

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
4.8CVSS 3.1MEDIUM——cvelistV5

Weakness & attack patterns

  • CWE-488

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1134.001Access Token Manipulation: Token Impersonation/Theft
  • T1550.004Use Alternate Authentication Material: Web Session Cookie

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Search application, proxy, and WAF logs for requests touching /jsx, /jsx-renderer, /context-storage.

References

1 on the record

Elsewhere on this site

  • honojsevery CVE for this vendor
  • CWE-488other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.