CVE-2026-59896 hono/jsx does not isolate context per request, leading to cross-request data disclosure
Attackers can access data from other users' requests due to shared context in Hono's JSX server-side rendering.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-59896?
CVE-2026-59896 is a medium-severity vulnerability in honojs hono, published on 8 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Hono is a Web application framework that provides support for any JavaScript runtime. From 4.11.8 before 4.12.27, hono/jsx did not isolate context values per request during server-side rendering, allowing createContext, useContext, jsxRenderer, or useRequestContext data from a different in-flight request to be used after an await in an async component. This issue is fixed in version 4.12.27.
Weakness: CWE-362
Which versions are affected by CVE-2026-59896?
2 open source packages ship an affected version, including hono. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
hono npm | From 4.11.8 | 4.12.27 |
hono npm | From 4.11.8 | 4.12.27 |
Products include Hono Hono.
How do I fix CVE-2026-59896?
Upgrade hono to 4.12.27 or later.
Is CVE-2026-59896 being exploited?
There is no known exploitation of CVE-2026-59896 in the wild and no public exploit code.
Other vulnerabilities in honojs hono
- CVE-2026-27700 Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo
- CVE-2026-22817 JWT Algorithm Confusion via Unsafe Default (HS256) in Hono JWT Middleware Allows Token Forgery and Auth Bypass
- CVE-2026-22818 JWT algorithm confusion in Hono JWK Auth Middleware when JWK lacks "alg" (untrusted header.alg fallback)
- CVE-2025-62610 Hono Improperly Authorizes JWT Audience Validation
- CVE-2026-29045 Hono: Arbitrary file access via serveStatic vulnerability
Sources
Also known as CLEANSTART-2026-BN50669, ECHO-bd5b-948e-fdde, GHSA-hvrm-45r6-mjfj, MINI-22xj-pcqq-w7pc, MINI-2462-jrp2-76hw, MINI-529j-mqm8-gp4m and 8 more.