diff --git a/core/lib/Drupal/Core/Database/Install/Tasks.php b/core/lib/Drupal/Core/Database/Install/Tasks.php
index a944c58..fb5b8c1 100644
--- a/core/lib/Drupal/Core/Database/Install/Tasks.php
+++ b/core/lib/Drupal/Core/Database/Install/Tasks.php
@@ -303,6 +303,11 @@ public function validateDatabaseSettings($database) {
       $errors[$database['driver'] . '][prefix'] = t('The database table prefix you have entered, %prefix, is invalid. The table prefix can only contain alphanumeric characters, periods, or underscores.', array('%prefix' => $database['prefix']));
     }
 
+    // Verify there are no illegal characters in the database name.
+    if (!empty($database['database']) && !preg_match('/^[A-Za-z0-9_.]+$/', $database['database'])) {
+      $errors[$database['driver'] . '][database'] = t('The database name you have entered, %database, is invalid. The database name can only contain alphanumeric characters, periods,  or underscores.', array('%database' => $database['database']));
+    }
+
     return $errors;
   }