diff --git a/library/HTMLPurifier/AttrDef/Border.php b/library/HTMLPurifier/AttrDef/Border.php
index df81f31e..f737cb1a 100644
--- a/library/HTMLPurifier/AttrDef/Border.php
+++ b/library/HTMLPurifier/AttrDef/Border.php
@@ -29,7 +29,7 @@ class HTMLPurifier_AttrDef_Border extends HTMLPurifier_AttrDef
         foreach ($bits as $bit) {
             foreach ($this->info as $propname => $validator) {
                 if (isset($done[$propname])) continue;
-                $r = $validator->validate($bit, $config, &$context);
+                $r = $validator->validate($bit, $config, $context);
                 if ($r !== false) {
                     $ret .= $r . ' ';
                     $done[$propname] = true;
diff --git a/library/HTMLPurifier/AttrDef/Font.php b/library/HTMLPurifier/AttrDef/Font.php
index 7ce21b12..4c987dcb 100644
--- a/library/HTMLPurifier/AttrDef/Font.php
+++ b/library/HTMLPurifier/AttrDef/Font.php
@@ -67,7 +67,7 @@ class HTMLPurifier_AttrDef_Font extends HTMLPurifier_AttrDef
                     foreach ($stage_1 as $validator_name) {
                         if (isset($caught[$validator_name])) continue;
                         $r = $this->info[$validator_name]->validate(
-                                                $bits[$i], $config, &$context);
+                                                $bits[$i], $config, $context);
                         if ($r !== false) {
                             $final .= $r . ' ';
                             $caught[$validator_name] = true;
@@ -94,7 +94,7 @@ class HTMLPurifier_AttrDef_Font extends HTMLPurifier_AttrDef
                         $line_height = false;
                     }
                     $r = $this->info['font-size']->validate(
-                                              $font_size, $config, &$context);
+                                              $font_size, $config, $context);
                     if ($r !== false) {
                         $final .= $r;
                         // attempt to catch line-height
@@ -121,7 +121,7 @@ class HTMLPurifier_AttrDef_Font extends HTMLPurifier_AttrDef
                         if ($found_slash) {
                             $i = $j;
                             $r = $this->info['line-height']->validate(
-                                              $line_height, $config, &$context);
+                                              $line_height, $config, $context);
                             if ($r !== false) {
                                 $final .= '/' . $r;
                             }
@@ -137,7 +137,7 @@ class HTMLPurifier_AttrDef_Font extends HTMLPurifier_AttrDef
                     $font_family =
                         implode(' ', array_slice($bits, $i, $size - $i));
                     $r = $this->info['font-family']->validate(
-                                              $font_family, $config, &$context);
+                                              $font_family, $config, $context);
                     if ($r !== false) {
                         $final .= $r . ' ';
                         // processing completed successfully