repostat: Reflected Cross-Site Scripting (XSS) via repo prop in RepoCard

Impact

The RepoCard component is vulnerable to Reflected Cross-Site Scripting (XSS). The vulnerability occurs because the component uses React's dangerouslySetInnerHTML to render the repository name (repo prop) during the loading state without any sanitization.

If a developer using this package passes unvalidated user input directly into the repo prop (for example, reading it from a URL query parameter), an attacker can execute arbitrary JavaScript in the context of the user's browser.

Proof of Concept

import { RepoCard } from 'repostat';

function App() {
  const params = new URLSearchParams(window.location.search);
  const maliciousRepo = params.get('repo') || 'facebook/react';

  return <RepoCard repo={maliciousRepo} token="YOUR_TOKEN" />;
}

Remediation

Update to version 1.0.1. The use of dangerouslySetInnerHTML has been removed, and the repo prop is now safely rendered using standard React JSX data binding, which automatically escapes HTML entities.