diff --git a/source/smbd/password.c b/source/smbd/password.c
index d15970cbefe..72292de4227 100644
--- a/source/smbd/password.c
+++ b/source/smbd/password.c
@@ -488,7 +488,11 @@ BOOL authorise_login(int snum, fstring user, DATA_BLOB password,
 	/* now check the list of session users */
 	if (!ok) {
 		char *auser;
-		char *user_list = strdup(session_userlist);
+		char *user_list = NULL;
+
+		if ( session_userlist )
+			user_list = strdup(session_userlist);
+
 		if (!user_list)
 			return(False);