Don't offer to save credit cards with an empty or 0 month.

components/autofill/core/browser/validation.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/autofill/core/browser/validation.h"
 
 #include <stddef.h>
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
@@ skipping 22 matching lines @@
   int cc_month;
   if (!base::StringToInt(month_cleaned, &cc_month))
     return false;
 
   return IsValidCreditCardExpirationDate(cc_year, cc_month, now);
 }
 
 bool IsValidCreditCardExpirationDate(int year,
                                      int month,
                                      const base::Time& now) {
+  if (month < 1 || month > 12)
+    return false;
+
   base::Time::Exploded now_exploded;
   now.LocalExplode(&now_exploded);
 
   if (year < now_exploded.year)
     return false;
 
   if (year == now_exploded.year && month < now_exploded.month)
     return false;
 
   return true;
@@ skipping 148 matching lines @@
                                              number_string.begin() + 9),
                          &serial)
       || serial == 0) {
     return false;
   }
 
   return true;
 }
 
 }  // namespace autofill