diff --git a/ChangeLog b/ChangeLog
index c5f0ac86c5..c73cc22c6e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -50,6 +50,7 @@ phpMyAdmin - ChangeLog
 - issue #15863 Fixed designer move menu icon not changing directions and tables menu list resize button
 - issue #15854 Fixed black borders for full screen mode on Designer
 - issue #15899 Fix "Uncaught TypeError: mb_strtoupper()" on the relational view of a view
+- issue        Fixed some php uncaught errors and notices on user missing extension
 
 5.0.1 (2020-01-07)
 - issue #15719 Fixed error 500 when browsing a table when $cfg['LimitChars'] used a string and not an int value
diff --git a/libraries/classes/Core.php b/libraries/classes/Core.php
index 3cea2dde9c..40ca72ea63 100644
--- a/libraries/classes/Core.php
+++ b/libraries/classes/Core.php
@@ -326,7 +326,7 @@ class Core
         ];
 
         $lang = 'en';
-        if (in_array($GLOBALS['lang'], $php_doc_languages)) {
+        if (isset($GLOBALS['lang']) && in_array($GLOBALS['lang'], $php_doc_languages)) {
             $lang = $GLOBALS['lang'];
         }
 
@@ -345,6 +345,9 @@ class Core
         bool $fatal = false,
         string $extra = ''
     ): void {
+        /** @var ErrorHandler $error_handler */
+        global $error_handler;
+
         /* Gettext does not have to be loaded yet here */
         if (function_exists('__')) {
             $message = __(
@@ -367,11 +370,11 @@ class Core
             return;
         }
 
-        $GLOBALS['error_handler']->addError(
+        $error_handler->addError(
             $message,
             E_USER_WARNING,
             '',
-            '',
+            0,
             false
         );
     }
diff --git a/libraries/classes/Template.php b/libraries/classes/Template.php
index de10a82485..10093810b4 100644
--- a/libraries/classes/Template.php
+++ b/libraries/classes/Template.php
@@ -55,11 +55,11 @@ class Template
     {
         global $cfg;
 
-        /** @var Config $config */
+        /** @var Config|null $config */
         $config = $GLOBALS['PMA_Config'];
         if (static::$twig === null) {
             $loader = new FilesystemLoader(self::BASE_PATH);
-            $cache_dir = $config->getTempDir('twig');
+            $cache_dir = $config !== null ? $config->getTempDir('twig') : null;
             /* Twig expects false when cache is not configured */
             if ($cache_dir === null) {
                 $cache_dir = false;
diff --git a/libraries/classes/Url.php b/libraries/classes/Url.php
index 765e048679..18e0852468 100644
--- a/libraries/classes/Url.php
+++ b/libraries/classes/Url.php
@@ -220,7 +220,9 @@ class Url
             $params['server'] = $GLOBALS['server'];
         }
 
-        if (empty($PMA_Config->getCookie('pma_lang')) && ! empty($GLOBALS['lang'])) {
+        // Can be null when the user is missing an extension.
+        // See: Core::checkExtensions()
+        if ($PMA_Config !== null && empty($PMA_Config->getCookie('pma_lang')) && ! empty($GLOBALS['lang'])) {
             $params['lang'] = $GLOBALS['lang'];
         }