diff --git a/lisp/net/tls.el b/lisp/net/tls.el
index 9de74ca19d4..ee093571dec 100644
--- a/lisp/net/tls.el
+++ b/lisp/net/tls.el
@@ -142,6 +142,7 @@ Fourth arg PORT is an integer specifying a port to connect to."
 	     response)
 	(while (and process
 		    (memq (process-status process) '(open run))
+		    buffer
 		    (save-excursion
 		      (set-buffer buffer) ;; XXX "blue moon" nntp.el bug
 		      (goto-char (point-min))