diff --git a/.jules/sentinel.md b/.jules/sentinel.md
new file mode 100644
index 0000000..66ce8b1
--- /dev/null
+++ b/.jules/sentinel.md
@@ -0,0 +1,4 @@
+## 2026-07-08 - XSS Prevention via Sandboxed iframes
+**Vulnerability:** Used dangerouslySetInnerHTML for email preview rendering, presenting an XSS risk even when used with DOMPurify.
+**Learning:** To prevent XSS when rendering dynamic or untrusted HTML like email previews, an isolated browsing context is safer.
+**Prevention:** Prioritize using a sandboxed <iframe> with the srcDoc attribute instead of dangerouslySetInnerHTML. Use sandbox='allow-popups allow-popups-to-escape-sandbox' to permit link clicking while omitting allow-scripts.
diff --git a/components/accounts/ppp-savings-panel.tsx b/components/accounts/ppp-savings-panel.tsx
index e6d961b..2038841 100644
--- a/components/accounts/ppp-savings-panel.tsx
+++ b/components/accounts/ppp-savings-panel.tsx
@@ -233,7 +233,11 @@ 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 }} />
+              <iframe
+                srcDoc={`<style>body { font-family: sans-serif; font-size: 14px; color: black; margin: 0; padding: 0; }</style>${sanitizedEmailHtml}`}
+                sandbox="allow-popups allow-popups-to-escape-sandbox"
+                className="h-full min-h-[24rem] w-full border-0"
+              />
             </div>
           </div>
         </div>