diff --git a/src-tauri/tauri.conf.json b/src-tauri/tauri.conf.json
index f22f281..166f9e5 100644
--- a/src-tauri/tauri.conf.json
+++ b/src-tauri/tauri.conf.json
@@ -23,7 +23,7 @@
       }
     ],
     "security": {
-      "csp": "default-src 'self'; script-src 'self' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; font-src 'self' data:; connect-src ipc: http://ipc.localhost https://open.er-api.com https://api.coingecko.com https://query1.finance.yahoo.com https://query2.finance.yahoo.com https://api.frankfurter.dev"
+      "csp": "default-src 'self'; script-src 'self' blob:; style-src 'self' 'unsafe-inline'; img-src 'self' data:; font-src 'self' data:; connect-src ipc: http://ipc.localhost https://open.er-api.com https://api.coingecko.com https://query1.finance.yahoo.com https://query2.finance.yahoo.com https://api.frankfurter.dev"
     }
   },
   "bundle": {
diff --git a/src/extensions.ts b/src/extensions.ts
index 73967ad..2085f52 100644
--- a/src/extensions.ts
+++ b/src/extensions.ts
@@ -16,14 +16,43 @@ export function makeApi(engine: SumEngine): ExtensionApi {
   };
 }
 
-export function runExtensions(engine: SumEngine, scripts: { name: string; code: string }[]): void {
+export async function runExtensions(engine: SumEngine, scripts: { name: string; code: string }[]): Promise<void> {
   const numi = makeApi(engine);
+  let id = 0;
   for (const s of scripts) {
-    try {
-      const fn = new Function("numi", s.code);
-      fn(numi);
-    } catch (e) {
-      console.error(`extension ${s.name} failed:`, e);
-    }
+    const globalName = `__numi_ext_${id++}`;
+    (window as any)[globalName] = numi;
+
+    const code = `
+      try {
+        (function(numi) {
+          ${s.code}
+        })(window.${globalName});
+      } catch (e) {
+        console.error(\`extension \${s.name} failed:\`, e);
+      }
+    `;
+
+    const blob = new Blob([code], { type: "text/javascript" });
+    const url = URL.createObjectURL(blob);
+    const script = document.createElement("script");
+    script.src = url;
+
+    await new Promise<void>((resolve) => {
+      script.onload = () => {
+        URL.revokeObjectURL(url);
+        delete (window as any)[globalName];
+        script.remove();
+        resolve();
+      };
+      script.onerror = (e) => {
+        console.error(`extension ${s.name} failed to load:`, e);
+        URL.revokeObjectURL(url);
+        delete (window as any)[globalName];
+        script.remove();
+        resolve();
+      };
+      document.head.appendChild(script);
+    });
   }
 }
diff --git a/src/main.ts b/src/main.ts
index a0d754b..bafc32a 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -710,7 +710,7 @@ async function boot(): Promise<void> {
   if (!data.docs.some((d) => d.id === data.activeId)) data.activeId = data.docs[0].id;
 
   const scripts = await loadExtensionScripts();
-  runExtensions(engine, scripts);
+  await runExtensions(engine, scripts);
 
   workspace = new Workspace(engine, () =>
     data.docs.map((d) => ({ id: d.id, title: d.title, text: data.contents[d.id] ?? "" })),