diff --git a/ChangeLog b/ChangeLog
index 0bcf3f6f5d..93b2186064 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -23,6 +23,7 @@ phpMyAdmin - ChangeLog
 4.6.4 (not yet released)
 - issue        Include X-Robots-Tag header in responses
 - issue        Enfornce numeric field length when creating table
+- issue        Fixed invalid Content-Length in some HTTP responses
 
 4.6.3 (2016-06-23)
 - issue #12249 Fixed cookie path on Windows
diff --git a/libraries/DisplayResults.php b/libraries/DisplayResults.php
index ac468155ff..a6f72d39c6 100644
--- a/libraries/DisplayResults.php
+++ b/libraries/DisplayResults.php
@@ -5263,7 +5263,7 @@ class DisplayResults
 
         if (isset($content)) {
 
-            $size = mb_strlen($content, '8bit');
+            $size = strlen($content);
             $display_size = Util::formatByteDown($size, 3, 1);
             $result .= ' - ' . $display_size[0] . ' ' . $display_size[1];
 
diff --git a/libraries/Linter.php b/libraries/Linter.php
index 5d0dd49515..422141e615 100644
--- a/libraries/Linter.php
+++ b/libraries/Linter.php
@@ -38,7 +38,7 @@ class Linter
             $str = new UtfString($str);
         }
 
-        // The reason for using the '8bit' parameter is that the length
+        // The reason for using the strlen is that the length
         // required is the length in bytes, not characters.
         //
         // Given the following string: `????+`, where `?` represents a
@@ -51,7 +51,7 @@ class Linter
         // (which is actually a new line) aren't going to be processed at
         // all.
         $len = ($str instanceof UtfString) ?
-            $str->length() : mb_strlen($len, '8bit');
+            $str->length() : strlen($len);
 
         $lines = array(0);
         for ($i = 0; $i < $len; ++$i) {
diff --git a/libraries/PDF.php b/libraries/PDF.php
index 3f7bad725e..efe9abfef3 100644
--- a/libraries/PDF.php
+++ b/libraries/PDF.php
@@ -141,7 +141,7 @@ class PDF extends TCPDF
         PMA_downloadHeader(
             $filename,
             'application/pdf',
-            mb_strlen($pdfData)
+            strlen($pdfData)
         );
         echo $pdfData;
     }
diff --git a/libraries/plugins/auth/AuthenticationCookie.php b/libraries/plugins/auth/AuthenticationCookie.php
index ddbf8fcddc..158983a4ac 100644
--- a/libraries/plugins/auth/AuthenticationCookie.php
+++ b/libraries/plugins/auth/AuthenticationCookie.php
@@ -687,7 +687,7 @@ class AuthenticationCookie extends AuthenticationPlugin
                 true
             );
         }
-        if (mb_strlen($this->_cookie_iv, '8bit') < $this->getIVSize()) {
+        if (strlen($this->_cookie_iv) < $this->getIVSize()) {
                 $this->createIV();
         }
 
diff --git a/libraries/plugins/schema/dia/Dia.php b/libraries/plugins/schema/dia/Dia.php
index f6793d400a..4aad6e067f 100644
--- a/libraries/plugins/schema/dia/Dia.php
+++ b/libraries/plugins/schema/dia/Dia.php
@@ -181,7 +181,7 @@ class Dia extends XMLWriter
         PMA_downloadHeader(
             $fileName,
             'application/x-dia-diagram',
-            mb_strlen($output)
+            strlen($output)
         );
         print $output;
     }
diff --git a/libraries/plugins/schema/eps/Eps.php b/libraries/plugins/schema/eps/Eps.php
index 42ec3a0171..de39521d6f 100644
--- a/libraries/plugins/schema/eps/Eps.php
+++ b/libraries/plugins/schema/eps/Eps.php
@@ -270,7 +270,7 @@ class Eps
         PMA_downloadHeader(
             $fileName,
             'image/x-eps',
-            mb_strlen($output)
+            strlen($output)
         );
         print $output;
     }
diff --git a/libraries/plugins/schema/svg/Svg.php b/libraries/plugins/schema/svg/Svg.php
index d7a4cc9358..0ea3c90adf 100644
--- a/libraries/plugins/schema/svg/Svg.php
+++ b/libraries/plugins/schema/svg/Svg.php
@@ -193,7 +193,7 @@ class Svg extends XMLWriter
         PMA_downloadHeader(
             $fileName,
             'image/svg+xml',
-            mb_strlen($output)
+            strlen($output)
         );
         print $output;
     }
diff --git a/libraries/tracking.lib.php b/libraries/tracking.lib.php
index 71e1a262c0..785c6fa8f1 100644
--- a/libraries/tracking.lib.php
+++ b/libraries/tracking.lib.php
@@ -1202,7 +1202,7 @@ function PMA_exportAsFileDownload($entries)
     PMA_downloadHeader(
         $filename,
         'text/x-sql',
-        mb_strlen($dump)
+        strlen($dump)
     );
     echo $dump;
 
diff --git a/tbl_get_field.php b/tbl_get_field.php
index 3e21c870aa..95f8b67b43 100644
--- a/tbl_get_field.php
+++ b/tbl_get_field.php
@@ -52,6 +52,6 @@ if ($result === false) {
 PMA_downloadHeader(
     $table . '-' .  $_GET['transform_key'] . '.bin',
     PMA_detectMIME($result),
-    mb_strlen($result, '8bit')
+    strlen($result)
 );
 echo $result;