diff --git a/django/contrib/auth/management/__init__.py b/django/contrib/auth/management/__init__.py
index 7abd2abcf4..7dcbfe4746 100644
--- a/django/contrib/auth/management/__init__.py
+++ b/django/contrib/auth/management/__init__.py
@@ -108,7 +108,7 @@ def get_default_username(check_db=True):
     default_username = get_system_username()
     try:
         default_username = unicodedata.normalize('NFKD', default_username)\
-            .encode('ascii', 'ignore').replace(' ', '').lower()
+            .encode('ascii', 'ignore').decode('ascii').replace(' ', '').lower()
     except UnicodeDecodeError:
         return ''
     if not RE_VALID_USERNAME.match(default_username):
diff --git a/django/contrib/auth/tests/tokens.py b/django/contrib/auth/tests/tokens.py
index beccfc5d07..44117a4f84 100644
--- a/django/contrib/auth/tests/tokens.py
+++ b/django/contrib/auth/tests/tokens.py
@@ -1,9 +1,11 @@
+import sys
 from datetime import date, timedelta
 
 from django.conf import settings
 from django.contrib.auth.models import User
 from django.contrib.auth.tokens import PasswordResetTokenGenerator
 from django.test import TestCase
+from django.utils import unittest
 
 
 class TokenGeneratorTest(TestCase):
@@ -51,6 +53,7 @@ class TokenGeneratorTest(TestCase):
         p2 = Mocked(date.today() + timedelta(settings.PASSWORD_RESET_TIMEOUT_DAYS + 1))
         self.assertFalse(p2.check_token(user, tk1))
 
+    @unittest.skipIf(sys.version_info[:2] >= (3, 0), "Unnecessary test with Python 3")
     def test_date_length(self):
         """
         Make sure we don't allow overly long dates, causing a potential DoS.
diff --git a/django/contrib/auth/views.py b/django/contrib/auth/views.py
index ccfc7a1003..c30d6ec6d0 100644
--- a/django/contrib/auth/views.py
+++ b/django/contrib/auth/views.py
@@ -200,7 +200,7 @@ def password_reset_confirm(request, uidb36=None, token=None,
     try:
         uid_int = base36_to_int(uidb36)
         user = User.objects.get(id=uid_int)
-    except (ValueError, User.DoesNotExist):
+    except (ValueError, OverflowError, User.DoesNotExist):
         user = None
 
     if user is not None and token_generator.check_token(user, token):