diff --git a/core/modules/user/src/PermissionHandler.php b/core/modules/user/src/PermissionHandler.php
index 1f07b25d95..1ab75f8dd8 100644
--- a/core/modules/user/src/PermissionHandler.php
+++ b/core/modules/user/src/PermissionHandler.php
@@ -70,6 +70,13 @@ class PermissionHandler implements PermissionHandlerInterface {
    */
   protected $controllerResolver;
 
+  /**
+   * List of permissions.
+   *
+   * @var array
+   */
+  protected $allPermissions = [];
+
   /**
    * Constructs a new PermissionHandler.
    *
@@ -105,17 +112,16 @@ protected function getYamlDiscovery() {
    * {@inheritdoc}
    */
   public function getPermissions() {
-    $all_permissions = $this->buildPermissionsYaml();
-
-    return $this->sortPermissions($all_permissions);
+    if (empty($this->allPermissions)) {
+      $this->allPermissions = $this->sortPermissions($this->buildPermissionsYaml());
+    }
+    return $this->allPermissions;
   }
 
   /**
    * {@inheritdoc}
    */
   public function moduleProvidesPermissions($module_name) {
-    // @TODO Static cache this information, see
-    // https://www.drupal.org/node/2339487
     $permissions = $this->getPermissions();
 
     foreach ($permissions as $permission) {
diff --git a/core/modules/user/tests/src/Traits/UserCreationTrait.php b/core/modules/user/tests/src/Traits/UserCreationTrait.php
index ccccfa77ff..30ab0e55ff 100644
--- a/core/modules/user/tests/src/Traits/UserCreationTrait.php
+++ b/core/modules/user/tests/src/Traits/UserCreationTrait.php
@@ -184,6 +184,9 @@ protected function createRole(array $permissions, $rid = NULL, $name = NULL, $we
    *   TRUE if the permissions are valid, FALSE otherwise.
    */
   protected function checkPermissions(array $permissions) {
+    // Reset the user.permissions service to reset statically cached
+    // permissions.
+    \Drupal::getContainer()->set('user.permissions', NULL);
     $available = array_keys(\Drupal::service('user.permissions')->getPermissions());
     $valid = TRUE;
     foreach ($permissions as $permission) {