diff --git a/src/applications/notification/controller/PhabricatorNotificationClearController.php b/src/applications/notification/controller/PhabricatorNotificationClearController.php
index a826ae0a6b..1d6c7f7b97 100644
--- a/src/applications/notification/controller/PhabricatorNotificationClearController.php
+++ b/src/applications/notification/controller/PhabricatorNotificationClearController.php
@@ -1,57 +1,68 @@
 <?php
 
 final class PhabricatorNotificationClearController
   extends PhabricatorNotificationController {
 
   public function handleRequest(AphrontRequest $request) {
     $viewer = $request->getViewer();
     $chrono_key = $request->getStr('chronoKey');
 
     if ($request->isDialogFormPost()) {
+      $should_clear = true;
+    } else {
+      try {
+        $request->validateCSRF();
+        $should_clear = true;
+      } catch (AphrontMalformedRequestException $ex) {
+        $should_clear = false;
+      }
+    }
+
+    if ($should_clear) {
       $table = new PhabricatorFeedStoryNotification();
 
       queryfx(
         $table->establishConnection('w'),
         'UPDATE %T SET hasViewed = 1 '.
         'WHERE userPHID = %s AND hasViewed = 0 and chronologicalKey <= %s',
         $table->getTableName(),
         $viewer->getPHID(),
         $chrono_key);
 
       PhabricatorUserCache::clearCache(
         PhabricatorUserNotificationCountCacheType::KEY_COUNT,
         $viewer->getPHID());
 
       return id(new AphrontReloadResponse())
         ->setURI('/notification/');
     }
 
     $dialog = new AphrontDialogView();
     $dialog->setUser($viewer);
     $dialog->addCancelButton('/notification/');
     if ($chrono_key) {
       $dialog->setTitle(pht('Really mark all notifications as read?'));
       $dialog->addHiddenInput('chronoKey', $chrono_key);
 
       $is_serious =
         PhabricatorEnv::getEnvConfig('phabricator.serious-business');
       if ($is_serious) {
         $dialog->appendChild(
           pht(
             'All unread notifications will be marked as read. You can not '.
             'undo this action.'));
       } else {
         $dialog->appendChild(
           pht(
             "You can't ignore your problems forever, you know."));
       }
 
       $dialog->addSubmitButton(pht('Mark All Read'));
     } else {
       $dialog->setTitle(pht('No notifications to mark as read.'));
       $dialog->appendChild(pht('You have no unread notifications.'));
     }
 
     return id(new AphrontDialogResponse())->setDialog($dialog);
   }
 }