Vite is a website frontend framework. When Vite's HTML transformation is invoked manually via `server.transformIndexHtml`, the original request URL is passed in unmodified, and the `html` being transformed contains inline module scripts (`<script type="module">...</script>`), it is possible to inject arbitrary HTML into the transformed output by supplying a malicious URL query string to `server.transformIndexHtml`. Only apps using `appType: 'custom'` and using the default Vite HTML middleware are affected. The HTML entry must also contain an inline script. The attack requires a user to click on a malicious URL while running the dev server. Restricted files aren't exposed to the attacker. This issue has been addressed in vite.5, vite.1, and vite.12. There are no known workarounds for this vulnerability.

References:

https://github.com/vitejs/vite/security/advisories/GHSA-92r3-m2mg-pj97