diff --git a/core/core.services.yml b/core/core.services.yml
index 9e82af7..3cbf64c 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -521,7 +521,7 @@ services:
     class: Drupal\Core\Extension\RequiredModuleUninstallValidator
     tags:
       - { name: module_install.uninstall_validator }
-    arguments: ['@string_translation']
+    arguments: ['@string_translation', '@extension.list.module']
     lazy: true
   theme_handler:
     class: Drupal\Core\Extension\ThemeHandler
diff --git a/core/lib/Drupal/Core/Extension/ModuleInstaller.php b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
index c01aaa0..8947151 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
@@ -83,6 +83,8 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
     $extension_config = \Drupal::configFactory()->getEditable('core.extension');
     if ($enable_dependencies) {
       // Get all module data so we can find dependencies and sort.
+      // The module list needs to be reset so that it can re-scan and include
+      // any new modules that may have been added directly into the filesystem.
       $module_data = \Drupal::service('extension.list.module')->reset()->getList();
       $module_list = $module_list ? array_combine($module_list, $module_list) : [];
       if ($missing_modules = array_diff_key($module_list, $module_data)) {
diff --git a/core/lib/Drupal/Core/Extension/RequiredModuleUninstallValidator.php b/core/lib/Drupal/Core/Extension/RequiredModuleUninstallValidator.php
index 8b90f0d..6c01c42 100644
--- a/core/lib/Drupal/Core/Extension/RequiredModuleUninstallValidator.php
+++ b/core/lib/Drupal/Core/Extension/RequiredModuleUninstallValidator.php
@@ -13,13 +13,21 @@ class RequiredModuleUninstallValidator implements ModuleUninstallValidatorInterf
   use StringTranslationTrait;
 
   /**
+   * The module extension list.
+   *
+   * @var \Drupal\Core\Extension\ModuleExtensionList
+   */
+  protected $moduleExtensionList;
+
+  /**
    * Constructs a new RequiredModuleUninstallValidator.
    *
    * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
    *   The string translation service.
    */
-  public function __construct(TranslationInterface $string_translation) {
+  public function __construct(TranslationInterface $string_translation, ModuleExtensionList $extension_list_module) {
     $this->stringTranslation = $string_translation;
+    $this->moduleExtensionList = $extension_list_module;
   }
 
   /**
@@ -41,11 +49,17 @@ public function validate($module) {
    *   The name of the module.
    *
    * @return array
-   *   The module info, or NULL if that module does not exist.
+   *   The module info, or empty array if that module does not exist.
    */
   protected function getModuleInfoByModule($module) {
-    $modules = \Drupal::service('extension.list.module')->getList();
-    return isset($modules[$module]->info) ? $modules[$module]->info : [];
+    try {
+      return $this->moduleExtensionList->get($module)->info;
+    }
+    catch (\InvalidArgumentException $e) {
+      // @todo Replace with dedicated exception
+      // https://www.drupal.org/project/drupal/issues/2940203
+      return [];
+    }
   }
 
 }
diff --git a/core/modules/system/src/Form/ModulesListForm.php b/core/modules/system/src/Form/ModulesListForm.php
index 02a08a2..96e2db5 100644
--- a/core/modules/system/src/Form/ModulesListForm.php
+++ b/core/modules/system/src/Form/ModulesListForm.php
@@ -80,11 +80,11 @@ public static function create(ContainerInterface $container) {
     return new static(
       $container->get('module_handler'),
       $container->get('module_installer'),
+      $container->get('extension.list.module'),
       $container->get('keyvalue.expirable')->get('module_list'),
       $container->get('access_manager'),
       $container->get('current_user'),
-      $container->get('user.permissions'),
-      $container->get('extension.list.module')
+      $container->get('user.permissions')
     );
   }
 
@@ -95,6 +95,8 @@ public static function create(ContainerInterface $container) {
    *   The module handler.
    * @param \Drupal\Core\Extension\ModuleInstallerInterface $module_installer
    *   The module installer.
+   * @param \Drupal\Core\Extension\ModuleExtensionList $extension_list_module
+   *   The module extension list.
    * @param \Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface $key_value_expirable
    *   The key value expirable factory.
    * @param \Drupal\Core\Access\AccessManagerInterface $access_manager
@@ -104,14 +106,14 @@ public static function create(ContainerInterface $container) {
    * @param \Drupal\user\PermissionHandlerInterface $permission_handler
    *   The permission handler.
    */
-  public function __construct(ModuleHandlerInterface $module_handler, ModuleInstallerInterface $module_installer, KeyValueStoreExpirableInterface $key_value_expirable, AccessManagerInterface $access_manager, AccountInterface $current_user, PermissionHandlerInterface $permission_handler, ModuleExtensionList $extension_list_module) {
+  public function __construct(ModuleHandlerInterface $module_handler, ModuleInstallerInterface $module_installer, ModuleExtensionList $extension_list_module, KeyValueStoreExpirableInterface $key_value_expirable, AccessManagerInterface $access_manager, AccountInterface $current_user, PermissionHandlerInterface $permission_handler) {
     $this->moduleHandler = $module_handler;
     $this->moduleInstaller = $module_installer;
+    $this->moduleExtensionList = $extension_list_module;
     $this->keyValueExpirable = $key_value_expirable;
     $this->accessManager = $access_manager;
     $this->currentUser = $current_user;
     $this->permissionHandler = $permission_handler;
-    $this->moduleExtensionList = $extension_list_module;
   }
 
   /**
@@ -153,7 +155,9 @@ public function buildForm(array $form, FormStateInterface $form_state) {
     ];
 
     // Sort all modules by their names.
-    $modules = $this->moduleExtensionList->getList();
+    // The module list needs to be reset so that it can re-scan and include any
+    // new modules that may have been added directly into the filesystem.
+    $modules = $this->moduleExtensionList->reset()->getList();
     uasort($modules, 'system_sort_modules_by_info_name');
 
     // Iterate over each of the modules.
diff --git a/core/modules/system/src/Form/ModulesUninstallForm.php b/core/modules/system/src/Form/ModulesUninstallForm.php
index 9fcefc3..bf3a06e 100644
--- a/core/modules/system/src/Form/ModulesUninstallForm.php
+++ b/core/modules/system/src/Form/ModulesUninstallForm.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\system\Form;
 
+use Drupal\Core\Extension\ModuleExtensionList;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Extension\ModuleInstallerInterface;
 use Drupal\Core\Form\FormBase;
@@ -38,12 +39,20 @@ class ModulesUninstallForm extends FormBase {
   protected $keyValueExpirable;
 
   /**
+   * The module extension list.
+   *
+   * @var \Drupal\Core\Extension\ModuleExtensionList
+   */
+  protected $moduleExtensionList;
+
+  /**
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container) {
     return new static(
       $container->get('module_handler'),
       $container->get('module_installer'),
+      $container->get('extension.list.module'),
       $container->get('keyvalue.expirable')->get('modules_uninstall')
     );
   }
@@ -55,12 +64,15 @@ public static function create(ContainerInterface $container) {
    *   The module handler.
    * @param \Drupal\Core\Extension\ModuleInstallerInterface $module_installer
    *   The module installer.
+   * @param \Drupal\Core\Extension\ModuleExtensionList $extension_list_module
+   *   The module extension list.
    * @param \Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface $key_value_expirable
    *   The key value expirable factory.
    */
-  public function __construct(ModuleHandlerInterface $module_handler, ModuleInstallerInterface $module_installer, KeyValueStoreExpirableInterface $key_value_expirable) {
+  public function __construct(ModuleHandlerInterface $module_handler, ModuleInstallerInterface $module_installer, ModuleExtensionList $extension_list_module, KeyValueStoreExpirableInterface $key_value_expirable) {
     $this->moduleHandler = $module_handler;
     $this->moduleInstaller = $module_installer;
+    $this->moduleExtensionList = $extension_list_module;
     $this->keyValueExpirable = $key_value_expirable;
   }
 
@@ -78,11 +90,11 @@ public function buildForm(array $form, FormStateInterface $form_state) {
     // Make sure the install API is available.
     include_once DRUPAL_ROOT . '/core/includes/install.inc';
 
-    // Get a list of all available modules.
-    $modules = \Drupal::service('extension.list.module')->getList();
-    $uninstallable = array_filter($modules, function ($module) use ($modules) {
-      return empty($modules[$module->getName()]->info['required']) && $module->status;
-    });
+    // Get a list of all available modules that can be uninstalled.
+    $uninstallable = array_filter($this->moduleExtensionList->getList(),
+      function ($module) {
+        return empty($module->info['required']) && $module->status;
+      });
 
     // Include system.admin.inc so we can use the sort callbacks.
     $this->moduleHandler->loadInclude('system', 'inc', 'system.admin');
diff --git a/core/modules/update/src/UpdateManager.php b/core/modules/update/src/UpdateManager.php
index bc1c491..fae499c 100644
--- a/core/modules/update/src/UpdateManager.php
+++ b/core/modules/update/src/UpdateManager.php
@@ -4,6 +4,7 @@
 
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\DependencyInjection\DependencySerializationTrait;
+use Drupal\Core\Extension\ModuleExtensionList;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Extension\ThemeHandlerInterface;
 use Drupal\Core\KeyValueStore\KeyValueFactoryInterface;
@@ -68,6 +69,13 @@ class UpdateManager implements UpdateManagerInterface {
   protected $themeHandler;
 
   /**
+   * The module extension list.
+   *
+   * @var \Drupal\Core\Extension\ModuleExtensionList
+   */
+  protected $moduleExtensionList;
+
+  /**
    * Constructs a UpdateManager.
    *
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
@@ -82,8 +90,10 @@ class UpdateManager implements UpdateManagerInterface {
    *   The expirable key/value factory.
    * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
    *   The theme handler.
+   * @param \Drupal\Core\Extension\ModuleExtensionList $extension_list_module
+   *   The module extension list.
    */
-  public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, UpdateProcessorInterface $update_processor, TranslationInterface $translation, KeyValueFactoryInterface $key_value_expirable_factory, ThemeHandlerInterface $theme_handler) {
+  public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, UpdateProcessorInterface $update_processor, TranslationInterface $translation, KeyValueFactoryInterface $key_value_expirable_factory, ThemeHandlerInterface $theme_handler, ModuleExtensionList $extension_list_module = NULL) {
     $this->updateSettings = $config_factory->get('update.settings');
     $this->moduleHandler = $module_handler;
     $this->updateProcessor = $update_processor;
@@ -92,6 +102,7 @@ public function __construct(ConfigFactoryInterface $config_factory, ModuleHandle
     $this->themeHandler = $theme_handler;
     $this->availableReleasesTempStore = $key_value_expirable_factory->get('update_available_releases');
     $this->projects = [];
+    $this->moduleExtensionList = $extension_list_module;
   }
 
   /**
@@ -129,7 +140,7 @@ public function getProjects() {
       $this->projects = $this->projectStorage('update_project_projects');
       if (empty($this->projects)) {
         // Still empty, so we have to rebuild.
-        $module_data = \Drupal::service('extension.list.module')->getList();
+        $module_data = $this->getModuleExtensionList()->reset()->getList();
         $theme_data = $this->themeHandler->rebuildThemeData();
         $project_info = new ProjectInfo();
         $project_info->processInfoList($this->projects, $module_data, 'module', TRUE);
@@ -223,4 +234,16 @@ public function fetchDataBatch(&$context) {
     }
   }
 
+  /**
+   * Gets the module extension list.
+   *
+   * @return \Drupal\Core\Extension\ModuleExtensionList
+   */
+  protected function getModuleExtensionList() {
+    if ($this->moduleExtensionList === NULL) {
+      $this->moduleExtensionList = \Drupal::service('extension.list.module');
+    }
+    return $this->moduleExtensionList;
+  }
+
 }