diff --git a/phpseclib/Net/SFTP.php b/phpseclib/Net/SFTP.php
index 9a0213a6..dafd94c0 100644
--- a/phpseclib/Net/SFTP.php
+++ b/phpseclib/Net/SFTP.php
@@ -1120,6 +1120,9 @@ class SFTP extends SSH2
         $temp = &$this->stat_cache;
         $max = count($dirs) - 1;
         foreach ($dirs as $i => $dir) {
+            if (!is_array($temp)) {
+                return false;
+            }
             if ($i === $max) {
                 unset($temp[$dir]);
                 return true;
@@ -1146,6 +1149,9 @@ class SFTP extends SSH2
 
         $temp = &$this->stat_cache;
         foreach ($dirs as $dir) {
+            if (!is_array($temp)) {
+                return null;
+            }
             if (!isset($temp[$dir])) {
                 return null;
             }