CVSS 3.1
3.4 lowCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:NCVE-2026-126359
Hono: `css` helper does not escape a closing tag split between the template and an interpolated value, allowing HTML injection
Low (3.4) in honojs hono. Fixed in hono 4.13.16.
On this page
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
- CWE
- CWE-79 Improper Neutralization of Input During Web Page Generation (Cross-site Scripting)
- OWASP Top 10
- A05:2025 Injection
- Published
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Not in the NVD yet
- Record from
- the CVE List, synced
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| honojs hono | >= 3.12.0, < 4.13.16 |
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-3gg2-335m-rxc6 | npm | hono | >=3.12.0 <4.13.16 | 4.13.16 |
Attack patterns (CAPEC)
- CAPEC-63 Cross-Site Scripting (XSS) Likelihood: High · Severity: Very High
- CAPEC-85 AJAX Footprinting Likelihood: High · Severity: Low
- CAPEC-209 XSS Using MIME Type Mismatch Severity: Medium
- CAPEC-588 DOM-Based XSS Likelihood: High · Severity: Very High
- CAPEC-591 Reflected XSS Likelihood: High · Severity: Very High
- CAPEC-592 Stored XSS Likelihood: High · Severity: Very High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.