Answer in brief
CVE-2026-126359 records a Low severity (CVSS 3.4) vulnerability in Hono: `css` helper does not escape a closing tag split between the template and an interpolated value, allowing HTML injection. The current sources do not mark it as known exploited. The current feed maps honojs/hono (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 3.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps honojs/hono (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| honojs/honogeneric | >=3.12.0 <4.13.16 | 4.13.16 |
Published upstream
Nov 12, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 12, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 12, 2026
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.
Quoted source text, attributed separately from HOL analysis.