Vulnerability · Published Jun 24, 2026 · Assigned by VulnCheck

CVE-2026-56761hono - HTML Injection via Improper JSX Attribute Name Handling in SSR

Medium 4.3

In plain English

A medium-severity cross-site scripting in hono from hono. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.3Medium

Exploit odds (30 days)0.3%top 77.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

hono before 4.12.14 contains an html injection vulnerability in jsx server-side rendering that allows attackers to inject unintended html by using malformed attribute names. Attackers can craft specially crafted attribute keys containing characters like quotes or angle brackets to break html tag boundaries and inject arbitrary attributes or elements.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	hono	4.12.14	GHSA-458j-xx4x-4375

Affected products (as reported)

Vendor	Product	Versions
hono	hono	0 – before 4.12.14

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

References

GitHub Security Advisory (GHSA-458j-xx4x-4375) vendor-advisory
VulnCheck Advisory: hono - HTML Injection via Improper JSX Attribute Name Handling in SSR third-party-advisory