diff --git a/api/system-current.txt b/api/system-current.txt
index 376aad0..b7fc339 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -3920,6 +3920,7 @@
     method @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public void getLatestTetheringEntitlementValue(int, boolean, @NonNull android.net.ConnectivityManager.TetheringEntitlementValueListener, @Nullable android.os.Handler);
     method @RequiresPermission(anyOf={android.Manifest.permission.TETHER_PRIVILEGED, android.Manifest.permission.WRITE_SETTINGS}) public boolean isTetheringSupported();
     method @RequiresPermission(anyOf={"android.permission.NETWORK_SETTINGS", android.Manifest.permission.NETWORK_SETUP_WIZARD, "android.permission.NETWORK_STACK"}) public void setAirplaneMode(boolean);
+    method @RequiresPermission(android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK) public void startCaptivePortalApp(android.os.Bundle);
     method @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public void startTethering(int, boolean, android.net.ConnectivityManager.OnStartTetheringCallback);
     method @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public void startTethering(int, boolean, android.net.ConnectivityManager.OnStartTetheringCallback, android.os.Handler);
     method @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public void stopTethering(int);
diff --git a/api/test-current.txt b/api/test-current.txt
index 5b51d6e..94e83ea 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -934,6 +934,7 @@
   }
 
   public class ConnectivityManager {
+    method @RequiresPermission(android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK) public void startCaptivePortalApp(android.os.Bundle);
     field public static final String EXTRA_CAPTIVE_PORTAL_PROBE_SPEC = "android.net.extra.CAPTIVE_PORTAL_PROBE_SPEC";
     field public static final String EXTRA_CAPTIVE_PORTAL_USER_AGENT = "android.net.extra.CAPTIVE_PORTAL_USER_AGENT";
   }
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 8a141e2..2aca55a 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -3923,6 +3923,25 @@
     }
 
     /**
+     * Requests that the system open the captive portal app with the specified extras.
+     *
+     * <p>This endpoint is exclusively for use by the NetworkStack and is protected by the
+     * corresponding permission.
+     * @param appExtras Extras to include in the app start intent.
+     * @hide
+     */
+    @SystemApi
+    @TestApi
+    @RequiresPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK)
+    public void startCaptivePortalApp(Bundle appExtras) {
+        try {
+            mService.startCaptivePortalAppInternal(appExtras);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
      * Determine whether the device is configured to avoid bad wifi.
      * @hide
      */
diff --git a/core/java/android/net/IConnectivityManager.aidl b/core/java/android/net/IConnectivityManager.aidl
index 3a405d3..872671f 100644
--- a/core/java/android/net/IConnectivityManager.aidl
+++ b/core/java/android/net/IConnectivityManager.aidl
@@ -27,6 +27,7 @@
 import android.net.NetworkRequest;
 import android.net.NetworkState;
 import android.net.ProxyInfo;
+import android.os.Bundle;
 import android.os.IBinder;
 import android.os.Messenger;
 import android.os.ParcelFileDescriptor;
@@ -167,6 +168,7 @@
     void setAcceptUnvalidated(in Network network, boolean accept, boolean always);
     void setAvoidUnvalidated(in Network network);
     void startCaptivePortalApp(in Network network);
+    void startCaptivePortalAppInternal(in Bundle appExtras);
 
     boolean getAvoidBadWifi();
     int getMultipathPreference(in Network Network);
diff --git a/packages/NetworkStack/src/com/android/server/connectivity/NetworkMonitor.java b/packages/NetworkStack/src/com/android/server/connectivity/NetworkMonitor.java
index dbffa6d..0d6d080 100644
--- a/packages/NetworkStack/src/com/android/server/connectivity/NetworkMonitor.java
+++ b/packages/NetworkStack/src/com/android/server/connectivity/NetworkMonitor.java
@@ -61,6 +61,7 @@
 import android.net.util.Stopwatch;
 import android.net.wifi.WifiInfo;
 import android.net.wifi.WifiManager;
+import android.os.Bundle;
 import android.os.Message;
 import android.os.RemoteException;
 import android.os.SystemClock;
@@ -674,11 +675,11 @@
         public boolean processMessage(Message message) {
             switch (message.what) {
                 case CMD_LAUNCH_CAPTIVE_PORTAL_APP:
-                    final Intent intent = new Intent(
-                            ConnectivityManager.ACTION_CAPTIVE_PORTAL_SIGN_IN);
+                    final Bundle appExtras = new Bundle();
                     // OneAddressPerFamilyNetwork is not parcelable across processes.
-                    intent.putExtra(ConnectivityManager.EXTRA_NETWORK, new Network(mNetwork));
-                    intent.putExtra(ConnectivityManager.EXTRA_CAPTIVE_PORTAL,
+                    appExtras.putParcelable(
+                            ConnectivityManager.EXTRA_NETWORK, new Network(mNetwork));
+                    appExtras.putParcelable(ConnectivityManager.EXTRA_CAPTIVE_PORTAL,
                             new CaptivePortal(new ICaptivePortal.Stub() {
                                 @Override
                                 public void appResponse(int response) {
@@ -700,16 +701,14 @@
                                 }
                             }));
                     final CaptivePortalProbeResult probeRes = mLastPortalProbeResult;
-                    intent.putExtra(EXTRA_CAPTIVE_PORTAL_URL, probeRes.detectUrl);
+                    appExtras.putString(EXTRA_CAPTIVE_PORTAL_URL, probeRes.detectUrl);
                     if (probeRes.probeSpec != null) {
                         final String encodedSpec = probeRes.probeSpec.getEncodedSpec();
-                        intent.putExtra(EXTRA_CAPTIVE_PORTAL_PROBE_SPEC, encodedSpec);
+                        appExtras.putString(EXTRA_CAPTIVE_PORTAL_PROBE_SPEC, encodedSpec);
                     }
-                    intent.putExtra(ConnectivityManager.EXTRA_CAPTIVE_PORTAL_USER_AGENT,
+                    appExtras.putString(ConnectivityManager.EXTRA_CAPTIVE_PORTAL_USER_AGENT,
                             mCaptivePortalUserAgent);
-                    intent.setFlags(
-                            Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT | Intent.FLAG_ACTIVITY_NEW_TASK);
-                    mContext.startActivityAsUser(intent, UserHandle.CURRENT);
+                    mCm.startCaptivePortalApp(appExtras);
                     return HANDLED;
                 default:
                     return NOT_HANDLED;
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 80b3d67..e6129f4 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -3240,6 +3240,25 @@
         });
     }
 
+    /**
+     * NetworkStack endpoint to start the captive portal app. The NetworkStack needs to use this
+     * endpoint as it does not have INTERACT_ACROSS_USERS_FULL itself.
+     * @param appExtras Bundle to use as intent extras for the captive portal application.
+     *                  Must be treated as opaque to avoid preventing the captive portal app to
+     *                  update its arguments.
+     */
+    @Override
+    public void startCaptivePortalAppInternal(Bundle appExtras) {
+        mContext.checkCallingOrSelfPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK);
+
+        final Intent appIntent = new Intent(ConnectivityManager.ACTION_CAPTIVE_PORTAL_SIGN_IN);
+        appIntent.putExtras(appExtras);
+        appIntent.setFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT | Intent.FLAG_ACTIVITY_NEW_TASK);
+
+        Binder.withCleanCallingIdentity(() ->
+                mContext.startActivityAsUser(appIntent, UserHandle.CURRENT));
+    }
+
     public boolean avoidBadWifi() {
         return mMultinetworkPolicyTracker.getAvoidBadWifi();
     }