diff --git a/core/modules/user/src/PermissionHandler.php b/core/modules/user/src/PermissionHandler.php
index 056c435dff..6607c0e56c 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 +112,18 @@ 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());
+      // Invoke hook_permissions_alter().
+      $this->moduleHandler->alter('permissions', $this->allPermissions);
+    }
+    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 9d687fd4e5..4024e4484e 100644
--- a/core/modules/user/tests/src/Traits/UserCreationTrait.php
+++ b/core/modules/user/tests/src/Traits/UserCreationTrait.php
@@ -307,6 +307,9 @@ 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 $permission) {
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 74ce5de07c..26eaee25e0 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -1350,12 +1350,24 @@ function user_form_process_password_confirm($element) {
   return $element;
 }
 
+/**
+ * Implements hook_modules_installed().
+ */
+function user_modules_installed($modules) {
+  // Reset the user.permissions service to reset statically cached
+  // permissions.
+  \Drupal::getContainer()->set('user.permissions', NULL);
+}
+
 /**
  * Implements hook_modules_uninstalled().
  */
 function user_modules_uninstalled($modules) {
   // Remove any potentially orphan module data stored for users.
   \Drupal::service('user.data')->delete($modules);
+  // Reset the user.permissions service to reset statically cached
+  // permissions.
+  \Drupal::getContainer()->set('user.permissions', NULL);
 }
 
 /**