diff --git a/src/Core/Addon.php b/src/Core/Addon.php
index 7957e08350..06a731b2cd 100644
--- a/src/Core/Addon.php
+++ b/src/Core/Addon.php
@@ -6,6 +6,7 @@ namespace Friendica\Core;
 
 use Friendica\BaseObject;
 use Friendica\Database\DBA;
+use Friendica\Util\Strings;
 
 /**
  * Some functions to handle addons
@@ -81,6 +82,8 @@ class Addon extends BaseObject
 	 */
 	public static function uninstall($addon)
 	{
+		$addon = Strings::sanitizeFilePathItem($addon);
+
 		Logger::notice("Addon {addon}: {action}", ['action' => 'uninstall', 'addon' => $addon]);
 		DBA::delete('addon', ['name' => $addon]);
 
@@ -102,11 +105,13 @@ class Addon extends BaseObject
 	 */
 	public static function install($addon)
 	{
-		// silently fail if addon was removed
+		$addon = Strings::sanitizeFilePathItem($addon);
 
+		// silently fail if addon was removed of if $addon is funky
 		if (!file_exists('addon/' . $addon . '/' . $addon . '.php')) {
 			return false;
 		}
+
 		Logger::notice("Addon {addon}: {action}", ['action' => 'install', 'addon' => $addon]);
 		$t = @filemtime('addon/' . $addon . '/' . $addon . '.php');
 		@include_once('addon/' . $addon . '/' . $addon . '.php');
@@ -130,6 +135,7 @@ class Addon extends BaseObject
 			if (!self::isEnabled($addon)) {
 				self::$addons[] = $addon;
 			}
+
 			return true;
 		} else {
 			Logger::error("Addon {addon}: {action} failed", ['action' => 'uninstall', 'addon' => $addon]);
@@ -153,29 +159,26 @@ class Addon extends BaseObject
 
 			$addon_list = explode(',', $addons);
 
-			if (count($addon_list)) {
-				foreach ($addon_list as $addon) {
-					$addon = trim($addon);
-					$fname = 'addon/' . $addon . '/' . $addon . '.php';
+			foreach ($addon_list as $addon) {
+				$addon = Strings::sanitizeFilePathItem(trim($addon));
+				$fname = 'addon/' . $addon . '/' . $addon . '.php';
+				if (file_exists($fname)) {
+					$t = @filemtime($fname);
+					foreach ($installed as $i) {
+						if (($i['name'] == $addon) && ($i['timestamp'] != $t)) {
 
-					if (file_exists($fname)) {
-						$t = @filemtime($fname);
-						foreach ($installed as $i) {
-							if (($i['name'] == $addon) && ($i['timestamp'] != $t)) {
+							Logger::notice("Addon {addon}: {action}", ['action' => 'reload', 'addon' => $i['name']]);
+							@include_once($fname);
 
-								Logger::notice("Addon {addon}: {action}", ['action' => 'reload', 'addon' => $i['name']]);
-								@include_once($fname);
-
-								if (function_exists($addon . '_uninstall')) {
-									$func = $addon . '_uninstall';
-									$func(self::getApp());
-								}
-								if (function_exists($addon . '_install')) {
-									$func = $addon . '_install';
-									$func(self::getApp());
-								}
-								DBA::update('addon', ['timestamp' => $t], ['id' => $i['id']]);
+							if (function_exists($addon . '_uninstall')) {
+								$func = $addon . '_uninstall';
+								$func(self::getApp());
 							}
+							if (function_exists($addon . '_install')) {
+								$func = $addon . '_install';
+								$func(self::getApp());
+							}
+							DBA::update('addon', ['timestamp' => $t], ['id' => $i['id']]);
 						}
 					}
 				}
@@ -204,6 +207,8 @@ class Addon extends BaseObject
 	{
 		$a = self::getApp();
 
+		$addon = Strings::sanitizeFilePathItem($addon);
+
 		$info = [
 			'name' => $addon,
 			'description' => "",
diff --git a/src/Core/Hook.php b/src/Core/Hook.php
index 7f0c015b3d..5caa543194 100644
--- a/src/Core/Hook.php
+++ b/src/Core/Hook.php
@@ -7,6 +7,7 @@ namespace Friendica\Core;
 use Friendica\App;
 use Friendica\BaseObject;
 use Friendica\Database\DBA;
+use Friendica\Util\Strings;
 
 /**
  * Some functions to handle hooks
@@ -215,6 +216,8 @@ class Hook extends BaseObject
 	 */
 	public static function isAddonApp($name)
 	{
+		$name = Strings::sanitizeFilePathItem($name);
+
 		if (array_key_exists('app_menu', self::$hooks)) {
 			foreach (self::$hooks['app_menu'] as $hook) {
 				if ($hook[0] == 'addon/' . $name . '/' . $name . '.php') {
diff --git a/src/Core/L10n.php b/src/Core/L10n.php
index f7ed9918ce..ae0ed18c3d 100644
--- a/src/Core/L10n.php
+++ b/src/Core/L10n.php
@@ -6,6 +6,7 @@ namespace Friendica\Core;
 
 use Friendica\BaseObject;
 use Friendica\Database\DBA;
+use Friendica\Util\Strings;
 
 /**
  * Provide Language, Translation, and Localization functions to the application
@@ -193,6 +194,8 @@ class L10n extends BaseObject
 	 */
 	private static function loadTranslationTable($lang)
 	{
+		$lang = Strings::sanitizeFilePathItem($lang);
+
 		if ($lang === self::$lang) {
 			return;
 		}
@@ -203,7 +206,7 @@ class L10n extends BaseObject
 		// load enabled addons strings
 		$addons = DBA::select('addon', ['name'], ['installed' => true]);
 		while ($p = DBA::fetch($addons)) {
-			$name = $p['name'];
+			$name = Strings::sanitizeFilePathItem($p['name']);
 			if (file_exists("addon/$name/lang/$lang/strings.php")) {
 				include "addon/$name/lang/$lang/strings.php";
 			}