CVE-2026-126359

Description

Hono is a Web application framework that provides support for any JavaScript runtime. From 3.12.0 until 4.13.16, the css helper in hono/css escapes interpolated string values separately and therefore fails to neutralize a closing style tag when < ends the template text or a preceding value and / begins the next attacker-controlled value. During server-side rendering, the combined output can close the <Style /> element early and cause the remainder of the interpolated value to be interpreted as HTML. Applications that place an untrusted string immediately after < in a css template, including adjacent untrusted interpolations, can expose viewers to attacker-controlled HTML or script and information accessible to that page. Other uses of the css helper are not affected. This issue is fixed in version 4.13.16.

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

• 3.4CVSS 3.1, Lowfrom the CNA (GitHub_M)CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Timeline

1. 12 Nov 2026 Published

Weakness

• CWE-79

References

• https://github.com/honojs/hono/security/advisories/GHSA-3gg2-335m-rxc6x_refsource_CONFIRM
• https://github.com/honojs/hono/commit/15bbd96ad1b62a0b189db4fd8dc7bf8ef280c513x_refsource_MISC
• https://github.com/honojs/hono/releases/tag/v4.13.16x_refsource_MISC