diff --git a/phpBB/adm/swatch.php b/phpBB/adm/swatch.php
index 2c5123b5e8..d11f2edd25 100644
--- a/phpBB/adm/swatch.php
+++ b/phpBB/adm/swatch.php
@@ -47,7 +47,7 @@ td {
 
 function cell(color)
 {
-	opener.document.forms['<?php echo htmlspecialchars($_GET['form']); ?>'].<?php echo htmlspecialchars($_GET['name']); ?>.value = '#' + color;
+	opener.document.forms['<?php echo htmlspecialchars(addslashes($_GET['form'])); ?>'].<?php echo htmlspecialchars(addslashes($_GET['name'])); ?>.value = '#' + color;
 }
 //-->
 </script>