## Hono JSX Security Flaw: Malformed Attribute Keys Enable Server-Side HTML Injection (GHSA-458j-xx4x-4375)
A critical security vulnerability in the popular Hono web framework exposes applications to server-side HTML injection attacks. The flaw, tracked as GHSA-458j-xx4x-4375, resides in the framework's JSX rendering engine. Improper handling of attribute names allows an attacker to use specially crafted, malformed attribute keys to break out of HTML attribute or tag boundaries during server-side rendering (SSR). This corruption of the generated HTML output can lead to unintended code execution.

The vulnerability is specific to the `hono/jsx` component and is triggered when untrusted user input is directly used as attribute keys in JSX templates. Under normal operation, attribute keys define HTML element properties. However, the flawed parsing logic fails to sanitize these keys, enabling a malicious payload to escape its intended context and inject arbitrary HTML into the final page served to users. This represents a direct threat to the integrity and security of any Hono-based application performing SSR with external data.

The maintainers have released patched versions `4.12.13` and `4.12.14` to address this issue. The update is marked as a security priority, prompting automated dependency managers like Renovate to flag it. The risk is confined to server-side rendering scenarios; client-side rendering is not affected. Developers must immediately update their `hono` dependency to mitigate the risk of this injection vector, which could be exploited to perform cross-site scripting (XSS) or other client-side attacks against end-users.
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- **Source**: GitHub Issues
- **Sector**: The Lab
- **Tags**: security, vulnerability, web-framework, jsx, ssr
- **Credibility**: unverified
- **Published**: 2026-04-16 19:23:03
- **ID**: 68066
- **URL**: https://whisperx.ai/en/intel/68066