CVE-2026-44458: hono Injection

Vulnerability summary

CVE-2026-44458 is a medium (CVSS 4.3) Injection vulnerability in hono. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 25.6% of scored vulnerabilities.

Timeline

1. 13-05-2026
   PublishedVulnerability first disclosed.
2. 14-05-2026
   Last modifiedVulnerability information updated.

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.18, the JSX renderer escapes style attribute object values for HTML but not for CSS. Untrusted input in a style object value or property name can therefore inject additional CSS declarations into the rendered style attribute. The impact is limited to CSS and does not allow JavaScript execution or HTML attribute breakout. This vulnerability is fixed in 4.12.18.

• CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
• CWE-116Improper Encoding or Escaping of OutputThe product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.