diff --git a/upload/common.php b/upload/common.php
index 0062edf4e..68ae49dc5 100644
--- a/upload/common.php
+++ b/upload/common.php
@@ -2086,9 +2086,17 @@ function log_request ($file = '', $prepend_str = false, $add_post = true)
 	if ($prepend_str !== false) $str[] = $prepend_str;
 	if (!empty($user->data)) $str[] = $user->id ."\t". html_entity_decode($user->name);
 	$str[] = sprintf('%-15s', $_SERVER['REMOTE_ADDR']);
-	$str[] = @$_SERVER['REQUEST_URI'];
-	$str[] = @$_SERVER['HTTP_USER_AGENT'];
-	$str[] = @$_SERVER['HTTP_REFERER'];
+
+    if (isset($_SERVER['REQUEST_URI'])) {
+        $str[] = $_SERVER['REQUEST_URI'];
+    }
+    if (isset($_SERVER['HTTP_USER_AGENT'])) {
+        $str[] = $_SERVER['HTTP_USER_AGENT'];
+    }
+    if (isset($_SERVER['HTTP_REFERER'])) {
+        $str[] = $_SERVER['HTTP_REFERER'];
+    }
+
 	if (!empty($_POST) && $add_post) $str[] = "post: ". str_compact(urldecode(http_build_query($_POST)));
 	$str = join("\t", $str) . "\n";
 	bb_log($str, $file);
diff --git a/upload/dl.php b/upload/dl.php
index 29f72bd3f..52045d945 100644
--- a/upload/dl.php
+++ b/upload/dl.php
@@ -207,7 +207,7 @@ else
 	{
 		global $template;
 
-		$redirect_url = !empty($_POST['redirect_url']) ? $_POST['redirect_url'] : @$_SERVER['HTTP_REFERER'];
+		$redirect_url = isset($_POST['redirect_url']) ? $_POST['redirect_url'] : (isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '/' );
 		$message = '<form action="'. DOWNLOAD_URL . $attachment['attach_id'] .'" method="post">';
 		$message .= $lang['CONFIRM_CODE'];
 		$message .= '<div class="mrg_10">'. CAPTCHA()->get_html() .'</div>';
diff --git a/upload/dl_list.php b/upload/dl_list.php
index 574c014a0..d4db8fd9c 100644
--- a/upload/dl_list.php
+++ b/upload/dl_list.php
@@ -5,9 +5,9 @@ define('BB_SCRIPT', 'dl_list');
 define('BB_ROOT', './');
 require(BB_ROOT .'common.php');
 
-$forum_id  = (@$_REQUEST[POST_FORUM_URL]) ? (int) $_REQUEST[POST_FORUM_URL] : 0;
-$topic_id  = (@$_REQUEST[POST_TOPIC_URL]) ? (int) $_REQUEST[POST_TOPIC_URL] : 0;
-$mode      = (@$_REQUEST['mode']) ? (string) $_REQUEST['mode'] : '';
+$forum_id  = isset($_REQUEST[POST_FORUM_URL]) ? (int) $_REQUEST[POST_FORUM_URL] : 0;
+$topic_id  = isset($_REQUEST[POST_TOPIC_URL]) ? (int) $_REQUEST[POST_TOPIC_URL] : 0;
+$mode      = isset($_REQUEST['mode']) ? (string) $_REQUEST['mode'] : '';
 $confirmed = isset($_POST['confirm']);
 
 // Get new DL-status
@@ -40,9 +40,9 @@ if ($mode == 'set_dl_status' || $mode == 'set_topics_dl_status')
 }
 
 // Define redirect URL
-$full_url = (@$_POST['full_url']) ? str_replace('&amp;', '&', htmlspecialchars($_POST['full_url'])) : '';
+$full_url = isset($_POST['full_url']) ? str_replace('&amp;', '&', htmlspecialchars($_POST['full_url'])) : '';
 
-if (@$_POST['redirect_type'] == 'search')
+if (isset($_POST['redirect_type']) && $_POST['redirect_type'] == 'search')
 {
 	$redirect_type = "search.php";
 	$redirect = ($full_url) ? $full_url : "$dl_key=1";
@@ -65,7 +65,7 @@ if (!$userdata['session_logged_in'])
 }
 
 // Check if user did not confirm
-if (@$_POST['cancel'])
+if (isset($_POST['cancel']) && $_POST['cancel'])
 {
 	redirect("$redirect_type?$redirect");
 }
diff --git a/upload/feed.php b/upload/feed.php
index 87b981957..454c6dd56 100644
--- a/upload/feed.php
+++ b/upload/feed.php
@@ -7,9 +7,9 @@ require(BB_ROOT .'common.php');
 
 $user->session_start(array('req_login' => true));
 
-$mode = (string) @$_REQUEST['mode'];
-$type = (string) @$_POST['type'];
-$id   = (int) @$_POST['id'];
+$mode = isset($_REQUEST['mode']) ? $_REQUEST['mode'] : '';
+$type = isset($_POST['type']) ? $_POST['type'] : '';
+$id   = isset($_POST['id']) ? $_POST['id'] : 0;
 $timecheck = TIMENOW - 600;
 
 if (!$mode) bb_simple_die($lang['ATOM_NO_MODE']);
diff --git a/upload/group.php b/upload/group.php
index 07fc133d6..38778d453 100644
--- a/upload/group.php
+++ b/upload/group.php
@@ -188,7 +188,7 @@ if (!$group_id)
 		else bb_die($lang['NO_GROUPS_EXIST']);
 	}
 }
-else if (@$_POST['joingroup'])
+else if (isset($_POST['joingroup']) && $_POST['joingroup'])
 {
 	if ($group_info['group_type'] != GROUP_OPEN)
 	{
@@ -263,7 +263,7 @@ else
 
 		if (!empty($_POST['add']))
 		{
-			if (!$row = get_userdata(@$_POST['username'], true))
+			if (isset($_POST['username']) && !($row = get_userdata($_POST['username'], true)))
 			{
 				bb_die($lang['COULD_NOT_ADD_USER']);
 			}
diff --git a/upload/library/includes/functions.php b/upload/library/includes/functions.php
index bac63225a..f10969194 100644
--- a/upload/library/includes/functions.php
+++ b/upload/library/includes/functions.php
@@ -1868,7 +1868,7 @@ function bb_realpath ($path)
 
 function login_redirect ($url = '')
 {
-    redirect(LOGIN_URL . '?redirect='. (($url) ? $url : (isset($_SERVER['REQUEST_URI']) ?: '/')));
+    redirect(LOGIN_URL . '?redirect='. (($url) ? $url : (isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '/')));
 }
 
 function meta_refresh ($url, $time = 5)
diff --git a/upload/login.php b/upload/login.php
index e959e2eb5..0a4ab9c1f 100644
--- a/upload/login.php
+++ b/upload/login.php
@@ -57,8 +57,8 @@ if (isset($_REQUEST['admin']) && !IS_AM) bb_die($lang['NOT_ADMIN']);
 $mod_admin_login = (IS_AM && !$user->data['session_admin']);
 
 // login username & password
-$login_username = ($mod_admin_login) ? $userdata['username'] : (string) @$_POST['login_username'];
-$login_password = (string) @$_POST['login_password'];
+$login_username = ($mod_admin_login) ? $userdata['username'] : (isset($_POST['login_username']) ? $_POST['login_username'] : '');
+$login_password = isset($_POST['login_password']) ? $_POST['login_password'] : '';
 
 // Проверка на неверную комбинацию логин/пароль
 $need_captcha = false;
diff --git a/upload/memberlist.php b/upload/memberlist.php
index fc0ff96bd..7a55374d0 100644
--- a/upload/memberlist.php
+++ b/upload/memberlist.php
@@ -108,7 +108,7 @@ $letters_range .= '-';
 $letters_range .= iconv('windows-1251', 'UTF-8', chr(255));
 $select_letter = $letter_sql = '';
 
-$by_letter_req = (@$_REQUEST['letter']) ? strtolower(trim($_REQUEST['letter'])) : false;
+$by_letter_req = isset($_REQUEST['letter']) ? strtolower(trim($_REQUEST['letter'])) : false;
 
 if ($by_letter_req)
 {
diff --git a/upload/modcp.php b/upload/modcp.php
index 0da5cffad..831e2a9fe 100644
--- a/upload/modcp.php
+++ b/upload/modcp.php
@@ -58,10 +58,22 @@ function validate_topics ($forum_id, &$req_topics, &$topic_titles)
 	$topic_titles = $valid_titles;
 }
 
+/**
+ * @param $request_index
+ * @param $mod_action
+ * @return bool
+ */
+function validate_mode_condition($request_index, $mod_action='') {
+    if (!$mod_action) {
+        $mod_action = $request_index;
+    }
+    return (isset($_REQUEST[$request_index]) || (isset($_POST['mod_action']) && $_POST['mod_action'] === $mod_action));
+}
+
 // Obtain initial vars
-$forum_id = (int) @$_REQUEST['f'];
-$topic_id = (int) @$_REQUEST['t'];
-$post_id  = (int) @$_REQUEST['p'];
+$forum_id = isset($_REQUEST['f']) ? $_REQUEST['f'] : 0;
+$topic_id = isset($_REQUEST['t']) ? $_REQUEST['t'] : 0;
+$post_id  = isset($_REQUEST['p']) ? $_REQUEST['p'] : 0;
 
 $start = isset($_REQUEST['start']) ? abs(intval($_REQUEST['start'])) : 0;
 $confirmed = isset($_POST['confirm']);
@@ -74,27 +86,27 @@ if (isset($_REQUEST['mode']))
 }
 else
 {
-	if (isset($_REQUEST['delete']) || @$_POST['mod_action'] === 'topic_delete')
+	if (validate_mode_condition('delete', 'topic_delete'))
 	{
 		$mode = 'delete';
 	}
-	elseif (isset($_REQUEST['move']) || @$_POST['mod_action'] === 'topic_move')
+	elseif (validate_mode_condition('move', 'topic_move'))
 	{
 		$mode = 'move';
 	}
-	elseif (isset($_REQUEST['lock']) || @$_POST['mod_action'] === 'topic_lock')
+	elseif (validate_mode_condition('lock', 'topic_lock'))
 	{
 		$mode = 'lock';
 	}
-	elseif (isset($_REQUEST['unlock']) || @$_POST['mod_action'] === 'topic_unlock')
+	elseif (validate_mode_condition('unlock', 'topic_unlock'))
 	{
 		$mode = 'unlock';
 	}
-	elseif (isset($_REQUEST['post_pin']) || @$_POST['mod_action'] === 'post_pin')
+	elseif (validate_mode_condition('post_pin'))
 	{
 		$mode = 'post_pin';
 	}
-	elseif (isset($_REQUEST['post_unpin']) || @$_POST['mod_action'] === 'post_unpin')
+	elseif (validate_mode_condition('post_unpin'))
 	{
 		$mode = 'post_unpin';
 	}