diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 41a3de31f2..0217aedb54 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -846,7 +846,7 @@ function phpbb_is_writable($file)
 */
 function phpbb_is_absolute($path)
 {
-	return ($path[0] == '/' || (DIRECTORY_SEPARATOR == '\\' && preg_match('#^[a-z]:[/\\\]#i', $path))) ? true : false;
+	return (isset($path[0]) && $path[0] == '/' || (DIRECTORY_SEPARATOR == '\\' && preg_match('#^[a-z]:[/\\\]#i', $path))) ? true : false;
 }
 
 /**
diff --git a/tests/functions/is_absolute_test.php b/tests/functions/is_absolute_test.php
index 64a7a81b4a..ada4d7b4de 100644
--- a/tests/functions/is_absolute_test.php
+++ b/tests/functions/is_absolute_test.php
@@ -14,6 +14,7 @@ class phpbb_functions_is_absolute_test extends phpbb_test_case
 	static public function is_absolute_data()
 	{
 		return array(
+			array('', false),
 			array('/etc/phpbb', true),
 			array('etc/phpbb', false),