diff --git a/lib/smb.php b/lib/smb.php
index ffc9b24..5b19199 100644
--- a/lib/smb.php
+++ b/lib/smb.php
@@ -43,7 +43,7 @@ class OC_User_SMB extends \OCA\user_external\Base{
 		$uidEscaped=escapeshellarg($uid);
 		$password=escapeshellarg($password);
 		$result=array();
-		$command=self::SMBCLIENT.' //'.$this->host.'/dummy -U'.$uidEscaped.'%'.$password;
+		$command=self::SMBCLIENT.' '.escapeshellarg('//' . $this->host . '/dummy').' -U'.$uidEscaped.'%'.$password;
 		$lastline = exec($command, $output, $retval);
 		if ($retval === 127) {
 			OCP\Util::writeLog(