PyModel
diff --git a/‎apps/pythinker-code/src/cli/sub/web/remote-control.ts‎
Lines changed: 14 additions & 1 deletion b/‎apps/pythinker-code/src/cli/sub/web/remote-control.ts‎
Lines changed: 14 additions & 1 deletion
diff --git a/‎apps/pythinker-code/test/cli/web/remote-control.test.ts‎
Lines changed: 11 additions & 0 deletions b/‎apps/pythinker-code/test/cli/web/remote-control.test.ts‎
Lines changed: 11 additions & 0 deletions
@@ -289,7 +289,7 @@ export function rewriteRemoteControlResponse(
 ): Buffer {
   const normalizedPrefix = publicPrefix.replace(/\/+$/, '');
   if (contentType.toLowerCase().includes('text/html')) {
-    const prefixLiteral = JSON.stringify(normalizedPrefix);
+    const prefixLiteral = scriptStringLiteral(normalizedPrefix);
     const injected = `<script>(function(){var p=${prefixLiteral};try{sessionStorage.setItem('pythinker-desktop-server-origin',location.origin+p)}catch(e){}var w=function(f){return function(s,t,u){if(typeof u==='string'&&u.charAt(0)==='/'&&u.indexOf(p)!==0)u=p+u;return f.apply(this,[s,t,u])}};history.pushState=w(history.pushState);history.replaceState=w(history.replaceState)})();</script>`;
     let text = body.toString('utf8');
     const headMatch = /<head(?:\s[^>]*)?>/i.exec(text);
@@ -316,6 +316,19 @@ export function rewriteRemoteControlResponse(
   return body;
 }
 
+/**
+ * Embed a value in an inline `<script>`. `JSON.stringify` alone is not enough:
+ * `</script>` in the value would close the element, and U+2028/U+2029 are line
+ * terminators inside a JavaScript string literal.
+ */
+function scriptStringLiteral(value: string): string {
+  return JSON.stringify(value)
+    .replaceAll('<', '\\u003c')
+    .replaceAll('>', '\\u003e')
+    .replaceAll('\u2028', '\\u2028')
+    .replaceAll('\u2029', '\\u2029');
+}
+
 export async function startRemoteControl(
   options: RemoteControlOptions,
 ): Promise<RemoteControlHandle> {
 
@@ -138,6 +138,17 @@ describe('Remote Control HTTP forwarding', () => {
     ).toThrow(SyntaxError);
   });
 
+  it('escapes the injected prefix so it cannot close the script element', () => {
+    const html = rewriteRemoteControlResponse(
+      'text/html',
+      Buffer.from('<html><head></head><body></body></html>'),
+      '/relay</script><script>alert(1)</script>/devices/d1',
+    ).toString();
+    expect(html).not.toContain('</script><script>alert(1)');
+    expect(html).toContain('\\u003c/script\\u003e');
+    expect(html.match(/<script>/g)).toHaveLength(1);
+  });
+
   it('rejects absolute-form and malformed request targets', () => {
     expect(() =>
       parseRawHttpRequest(Buffer.from('GET https://example.test/ HTTP/1.1\r\n\r\n')),