diff --git a/toolkit/components/securitylevel/SecurityLevel.jsm b/toolkit/components/securitylevel/SecurityLevel.jsm
index 79f5f2742dd99..25393c14f6317 100644
--- a/toolkit/components/securitylevel/SecurityLevel.jsm
+++ b/toolkit/components/securitylevel/SecurityLevel.jsm
@@ -161,6 +161,18 @@ let noscriptSettings = safetyLevel => ({
     enforced: true,
     autoAllowTop: false,
   },
+  sync: {
+    // Apply cross-tab identity leak protection to PBM windows
+    TabGuardMode: "incognito",
+    // Prompt only on problematic POST requests
+    TabGuardPrompt: "post",
+  },
+  // host-specific metadata
+  settingsHost: {
+    // help NoScript cooperate by versioning these settings
+    id: "mullvad",
+    version: 2,
+  },
   isTorBrowser: true,
   tabId: -1,
 });