diff --git a/mod/contacts.php b/mod/contacts.php
index 4e8769717..cfe968226 100644
--- a/mod/contacts.php
+++ b/mod/contacts.php
@@ -122,11 +122,12 @@ function contacts_init(App $a)
 
 function contacts_batch_actions(App $a)
 {
-	$contacts_id = $_POST['contact_batch'];
-	if (!is_array($contacts_id)) {
+	if (empty($_POST['contact_batch']) || !is_array($_POST['contact_batch'])) {
 		return;
 	}
 
+	$contacts_id = $_POST['contact_batch'];
+
 	$orig_records = q("SELECT * FROM `contact` WHERE `id` IN (%s) AND `uid` = %d AND `self` = 0",
 		implode(",", $contacts_id),
 		intval(local_user())
diff --git a/src/Module/Proxy.php b/src/Module/Proxy.php
index ccd00c604..7983e01f7 100644
--- a/src/Module/Proxy.php
+++ b/src/Module/Proxy.php
@@ -133,6 +133,10 @@ class Proxy extends BaseModule
 			$direct_cache = false;
 		}
 
+		if (empty($_REQUEST['url'])) {
+			System::httpExit(400, ["title" => L10n::t('Bad Request.')]);
+		}
+
 		if (!$direct_cache) {
 			$urlhash = 'pic:' . sha1($_REQUEST['url']);
 
diff --git a/src/Object/Image.php b/src/Object/Image.php
index 9506aedc2..620929df5 100644
--- a/src/Object/Image.php
+++ b/src/Object/Image.php
@@ -792,7 +792,7 @@ class Image
 
 			try {
 				if (function_exists("getimagesizefromstring")) {
-					$data = getimagesizefromstring($img_str);
+					$data = @getimagesizefromstring($img_str);
 				} else {
 					$tempfile = tempnam(get_temppath(), "cache");
 
diff --git a/src/Protocol/DFRN.php b/src/Protocol/DFRN.php
index 759f7f5f2..c43555031 100644
--- a/src/Protocol/DFRN.php
+++ b/src/Protocol/DFRN.php
@@ -2407,8 +2407,11 @@ class DFRN
 						break;
 					case "enclosure":
 						$enclosure = $href;
-						if (strlen($item["attach"])) {
+
+						if (!empty($item["attach"])) {
 							$item["attach"] .= ",";
+						} else {
+							$item["attach"] = "";
 						}
 
 						$item["attach"] .= '[attach]href="' . $href . '" length="' . $length . '" type="' . $type . '" title="' . $title . '"[/attach]';