diff --git a/Tests/OutputFilterTest.php b/Tests/OutputFilterTest.php
index 0be68520..33a8529e 100644
--- a/Tests/OutputFilterTest.php
+++ b/Tests/OutputFilterTest.php
@@ -230,6 +230,12 @@ public function testStripImages()
             $this->object->stripImages('Hello <<img>img src="wave.jpg"> I am waving at you.'),
             'Should remove nested img tags'
         );
+
+        $this->assertEquals(
+            'Hello  I am waving at you.',
+            $this->object->stripImages("Hello <img\nsrc=\"wave.jpg\" onerror=\"alert(1)\"> I am waving at you."),
+            'Should remove img tags containing newlines'
+        );
     }
 
     /**
@@ -260,6 +266,12 @@ public function testStripIframes()
             ),
             'Should remove nested iFrame tags'
         );
+
+        $this->assertEquals(
+            'Hello  I am waving at you.',
+            $this->object->stripIframes("Hello <iframe\nsrc=\"http://player.vimeo.com/video/37576499\"></iframe> I am waving at you."),
+            'Should remove iFrame tags containing newlines'
+        );
     }
 
     /**
diff --git a/src/OutputFilter.php b/src/OutputFilter.php
index af2d5e41..19221dad 100644
--- a/src/OutputFilter.php
+++ b/src/OutputFilter.php
@@ -263,8 +263,8 @@ public static function setLanguage(Language $language): void
      */
     public static function stripImages($string)
     {
-        while (preg_match('#(<[/]?img.*>)#Ui', $string)) {
-            $string = preg_replace('#(<[/]?img.*>)#Ui', '', $string);
+        while (preg_match('#(<[/]?img.*>)#Uis', $string)) {
+            $string = preg_replace('#(<[/]?img.*>)#Uis', '', $string);
         }
 
         return $string;
@@ -281,8 +281,8 @@ public static function stripImages($string)
      */
     public static function stripIframes($string)
     {
-        while (preg_match('#(<[/]?iframe.*>)#Ui', $string)) {
-            $string = preg_replace('#(<[/]?iframe.*>)#Ui', '', $string);
+        while (preg_match('#(<[/]?iframe.*>)#Uis', $string)) {
+            $string = preg_replace('#(<[/]?iframe.*>)#Uis', '', $string);
         }
 
         return $string;