Moderate severityNVD Advisory· Published Jul 8, 2026· Updated Jul 8, 2026
Hono: Server-Side XSS via JSX Escaping Bypass in cx() Utility
CVE-2026-59895
Description
Hono is a Web application framework that provides support for any JavaScript runtime. From 4.0.0 before 4.12.27, cx() in hono/css composes class names from plain strings but marks the result as already escaped without HTML-escaping the input, allowing untrusted className values used in a JSX class attribute during server-side rendering to break out of the attribute and inject arbitrary markup. This issue is fixed in version 4.12.27.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
hononpm | >= 4.0.0, < 4.12.27 | 4.12.27 |
Affected products
5- osv-coords4 versionspkg:apk/chainguard/langfuse-3-workerpkg:apk/chainguard/langfuse-fips-3-workerpkg:apk/chainguard/librechatpkg:apk/wolfi/langfuse-3-worker
< 3.224.1-r0+ 3 more
- (no CPE)range: < 3.224.1-r0
- (no CPE)range: < 3.224.1-r0
- (no CPE)range: < 0.8.7-r5
- (no CPE)range: < 3.224.1-r0
Patches
Vulnerability mechanics
References
5- github.com/advisories/GHSA-w62v-xxxg-mg59ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-59895ghsaADVISORY
- github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fcghsax_refsource_MISCWEB
- github.com/honojs/hono/releases/tag/v4.12.27ghsax_refsource_MISCWEB
- github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59ghsax_refsource_CONFIRMWEB
News mentions
0No linked articles in our index yet.