Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Hono | Hono | >= 4.0.0, < 4.12.27 |
Related Weaknesses (CWE)
References
- https://github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fcPatch
- https://github.com/honojs/hono/releases/tag/v4.12.27Release Notes
- https://github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59Vendor Advisory
FAQ
What is CVE-2026-59895?
CVE-2026-59895 is a vulnerability with a CVSS score of 6.1 (MEDIUM). 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 alread...
How severe is CVE-2026-59895?
CVE-2026-59895 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-59895?
Check the references section above for vendor advisories and patch information. Affected products include: Hono Hono.