CVE-2026-44458 PUBLISHED

Hono: CSS Declaration Injection via Style Object Values in JSX SSR

Assigner: GitHub_M
Reserved: 06.05.2026 Published: 13.05.2026 Updated: 13.05.2026

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.18, the JSX renderer escapes style attribute object values for HTML but not for CSS. Untrusted input in a style object value or property name can therefore inject additional CSS declarations into the rendered style attribute. The impact is limited to CSS and does not allow JavaScript execution or HTML attribute breakout. This vulnerability is fixed in 4.12.18.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
CVSS Score: 4.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	Low
User Interaction	Required	Availability Impact	None

CVSS 3.1

Product Status

Vendor	honojs
Product	hono
Versions	Version < 4.12.18 is affected

References

https://github.com/honojs/hono/security/advisories/GHSA-qp7p-654g-cw7p

Problem Types

CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') CWE
CWE-116: Improper Encoding or Escaping of Output CWE