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🛡️ Sentinel: [HIGH] Fix XSS vulnerability in email preview #349

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🛡️ Sentinel: [HIGH] Fix XSS vulnerability in email preview #349

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4 changes: 4 additions & 0 deletions .jules/sentinel.md
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Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
## 2024-07-04 - XSS Prevention via Sandboxed Iframe in Email Preview
**Vulnerability:** Email preview rendered using `dangerouslySetInnerHTML`.
**Learning:** Even with DOMPurify, rendering dynamic HTML directly into the DOM can lead to XSS or styling clashes. Using an `iframe` with `srcDoc` and a `sandbox` attribute (`allow-popups allow-popups-to-escape-sandbox`) provides true isolation without needing a separate endpoint.
**Prevention:** For untrusted or complex HTML previews, default to sandboxed iframes. Manually inject necessary styles into the `srcDoc` to ensure correct rendering.
28 changes: 26 additions & 2 deletions components/accounts/ppp-savings-panel.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -232,8 +232,32 @@ export function PppSavingsPanel({ orgSlug, accountId }: PppSavingsPanelProps) {
)}
</div>
</div>
<div className="min-h-[24rem] w-full overflow-auto bg-white p-6 text-sm text-black">
<div dangerouslySetInnerHTML={{ __html: sanitizedEmailHtml }} />
<div className="flex min-h-[24rem] w-full bg-white text-sm text-black">
<iframe
title="Email Preview"
className="w-full border-none h-full"
sandbox="allow-popups allow-popups-to-escape-sandbox"
srcDoc={`
<!DOCTYPE html>
<html>
<head>
<style>
body {
margin: 0;
padding: 1.5rem;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
font-size: 14px;
color: #000;
background-color: #fff;
}
</style>
</head>
<body>
${sanitizedEmailHtml}
</body>
</html>
`}
/>
</div>
</div>
</div>
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