CVE-2026-126359
Hono: `css` helper does not escape a closing tag split between the template and an interpolated value, allowing HTML injection
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.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| hono honojs |
>= 3.12.0, < 4.13.16 (affected) | CNA: GitHub_M |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 3.4 low |
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N | CNA: GitHub_M |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/honojs/hono/security/advisories/GHSA-3gg2-335m-rxc6CNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/honojs/hono/commit/15bbd96ad1b62a0b189db4fd8dc7bf8ef280c513CNA: GitHub_M · x_refsource_MISC
- https://github.com/honojs/hono/releases/tag/v4.13.16CNA: GitHub_M · x_refsource_MISC
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