CVE-2026-44458

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

State: Published
Severity: 4.3 Medium
Published: May 13, 2026
Updated: May 14, 2026
Reserved: May 6, 2026

Description

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.

Scores

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

Weaknesses

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

Affected Products

Product	Versions
honohonojs	< 4.12.18Affected

References

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

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