diff --git a/Lib/smtplib.py b/Lib/smtplib.py
index 8388b98..e1651c0 100755
--- a/Lib/smtplib.py
+++ b/Lib/smtplib.py
@@ -656,6 +656,11 @@
             self.ehlo_resp = None
             self.esmtp_features = {}
             self.does_esmtp = 0
+        else:
+            # RFC 3207:
+            # 501 Syntax error (no parameters allowed)
+            # 454 TLS not available due to temporary reason
+            raise SMTPResponseException(resp, reply)
         return (resp, reply)
 
     def sendmail(self, from_addr, to_addrs, msg, mail_options=[],
diff --git a/Misc/NEWS b/Misc/NEWS
index 4c643ef..313d913 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -92,6 +92,9 @@
 Library
 -------
 
+- Fix TLS stripping vulnerability in smptlib, CVE-2016-0772.  Reported by Team
+  Oststrom
+
 - Issue #7356: ctypes.util: Make parsing of ldconfig output independent of the
   locale.