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@5.0.5, vite@4.5.1, and vite@4.4.12. There are no known workarounds for this vulnerability.
Vite provides frontend tooling. Prior to versions 2.9.16, 3.2.7, 4.0.5, 4.1.5, 4.2.3, and 4.3.9, Vite Server Options (`server.fs.deny`) can be bypassed using double forward-slash (//) allows any unauthenticated user to read file from the Vite root-path of the application including the default `fs.deny` settings (`['.env', '.env.*', '*.{crt,pem}']`). Only users explicitly exposing the Vite dev server to the network (using `--host` or `server.host` config option) are affected, and only files in the immediate Vite project root folder could be exposed. This issue is fixed in vite@4.3.9, vite@4.2.3, vite@4.1.5, vite@4.0.5, vite@3.2.7, and vite@2.9.16.