diff --git a/src/com/android/settings/applications/specialaccess/notificationaccess/ApprovalPreferenceController.java b/src/com/android/settings/applications/specialaccess/notificationaccess/ApprovalPreferenceController.java
index a43b9fd9145..9235494f359 100644
--- a/src/com/android/settings/applications/specialaccess/notificationaccess/ApprovalPreferenceController.java
+++ b/src/com/android/settings/applications/specialaccess/notificationaccess/ApprovalPreferenceController.java
@@ -81,6 +81,9 @@ public class ApprovalPreferenceController extends BasePreferenceController {
         final SwitchPreference preference = (SwitchPreference) pref;
         final CharSequence label = mPkgInfo.applicationInfo.loadLabel(mPm);
         preference.setChecked(isServiceEnabled(mCn));
+        final boolean isAllowedCn = mCn.flattenToShortString().length()
+                <= NotificationManager.MAX_SERVICE_COMPONENT_NAME_LENGTH;
+        preference.setEnabled(preference.isChecked() || isAllowedCn);
         preference.setOnPreferenceChangeListener((p, newValue) -> {
             final boolean access = (Boolean) newValue;
             if (!access) {
diff --git a/src/com/android/settings/notification/NotificationAccessConfirmationActivity.java b/src/com/android/settings/notification/NotificationAccessConfirmationActivity.java
index dfe6df2a5ca..a6b565ae6ba 100644
--- a/src/com/android/settings/notification/NotificationAccessConfirmationActivity.java
+++ b/src/com/android/settings/notification/NotificationAccessConfirmationActivity.java
@@ -67,7 +67,9 @@ public class NotificationAccessConfirmationActivity extends Activity
         mUserId = getIntent().getIntExtra(EXTRA_USER_ID, UserHandle.USER_NULL);
         CharSequence mAppLabel;
 
-        if (mComponentName == null || mComponentName.getPackageName() == null) {
+        if (mComponentName == null || mComponentName.getPackageName() == null
+                || mComponentName.flattenToString().length()
+                > NotificationManager.MAX_SERVICE_COMPONENT_NAME_LENGTH) {
             finish();
             return;
         }
diff --git a/src/com/android/settings/notification/NotificationAccessSettings.java b/src/com/android/settings/notification/NotificationAccessSettings.java
index ab2a177bcf8..00543a2f3c0 100644
--- a/src/com/android/settings/notification/NotificationAccessSettings.java
+++ b/src/com/android/settings/notification/NotificationAccessSettings.java
@@ -63,7 +63,6 @@ public class NotificationAccessSettings extends EmptyTextSettings {
     private static final String TAG = "NotifAccessSettings";
     static final String ALLOWED_KEY = "allowed";
     static final String NOT_ALLOWED_KEY = "not_allowed";
-    private static final int MAX_CN_LENGTH = 500;
 
     private static final ManagedServiceSettings.Config CONFIG =
             new ManagedServiceSettings.Config.Builder()
@@ -145,7 +144,8 @@ public class NotificationAccessSettings extends EmptyTextSettings {
         for (ServiceInfo service : services) {
             final ComponentName cn = new ComponentName(service.packageName, service.name);
             boolean isAllowed = mNm.isNotificationListenerAccessGranted(cn);
-            if (!isAllowed && cn.flattenToString().length() > MAX_CN_LENGTH) {
+            if (!isAllowed && cn.flattenToString().length()
+                    > NotificationManager.MAX_SERVICE_COMPONENT_NAME_LENGTH) {
                 continue;
             }
 
diff --git a/tests/unit/src/com/android/settings/applications/specialaccess/notificationaccess/ApprovalPreferenceControllerTest.java b/tests/unit/src/com/android/settings/applications/specialaccess/notificationaccess/ApprovalPreferenceControllerTest.java
index 064f8134c67..5316adc1c3a 100644
--- a/tests/unit/src/com/android/settings/applications/specialaccess/notificationaccess/ApprovalPreferenceControllerTest.java
+++ b/tests/unit/src/com/android/settings/applications/specialaccess/notificationaccess/ApprovalPreferenceControllerTest.java
@@ -77,6 +77,25 @@ public class ApprovalPreferenceControllerTest {
         mController.setPkgInfo(mPkgInfo);
     }
 
+    @Test
+    public void updateState_enabled() {
+        SwitchPreference pref = new SwitchPreference(mContext);
+        mController.updateState(pref);
+        assertThat(pref.isEnabled()).isTrue();
+    }
+
+    @Test
+    public void updateState_invalidCn_disabled() {
+        ComponentName longCn = new ComponentName("com.example.package",
+                com.google.common.base.Strings.repeat("Blah", 150));
+        mController.setCn(longCn);
+        SwitchPreference pref = new SwitchPreference(mContext);
+
+        mController.updateState(pref);
+
+        assertThat(pref.isEnabled()).isFalse();
+    }
+
     @Test
     public void updateState_checked() {
         when(mNm.isNotificationListenerAccessGranted(mCn)).thenReturn(true);