diff -r 865cf8eba51a Lib/ipaddress.py
--- a/Lib/ipaddress.py	Mon Feb 29 11:25:09 2016 +0000
+++ b/Lib/ipaddress.py	Tue Mar 01 15:13:16 2016 +0800
@@ -916,7 +916,7 @@
                     new_prefixlen, self))
 
         start = int(self.network_address)
-        end = int(self.broadcast_address)
+        end = int(self.broadcast_address) + 1
         step = (int(self.hostmask) + 1) >> prefixlen_diff
         for new_addr in range(start, end, step):
             current = self.__class__((new_addr, new_prefixlen))
diff -r 865cf8eba51a Lib/test/test_ipaddress.py
--- a/Lib/test/test_ipaddress.py	Mon Feb 29 11:25:09 2016 +0000
+++ b/Lib/test/test_ipaddress.py	Tue Mar 01 15:13:16 2016 +0800
@@ -1053,10 +1053,15 @@
         self.assertEqual(subnets1, subnets2)
 
     def testSubnet2(self):
-        ips = [str(x) for x in self.ipv4_network.subnets(2)]
+        ips1 = [str(x) for x in self.ipv4_network.subnets(2)]
         self.assertEqual(
-            ips,
+            ips1,
             ['1.2.3.0/26', '1.2.3.64/26', '1.2.3.128/26', '1.2.3.192/26'])
+        # issue26457
+        ips2 = [str(x) for x in ipaddress.ip_network('192.0.2.0/31').subnets()]
+        self.assertEqual(
+            ips2,
+            ['192.0.2.0/32', '192.0.2.1/32'])
 
         ipsv6 = [str(x) for x in self.ipv6_network.subnets(2)]
         self.assertEqual(
@@ -1677,6 +1682,13 @@
         self.assertRaises(TypeError, list, addr1.address_exclude(addr4))
         self.assertRaises(TypeError, list, addr1.address_exclude(addr5))
         self.assertEqual(list(addr1.address_exclude(addr1)), [])
+        # issue26457
+        addr6 = ipaddress.ip_network('192.0.2.0/28')
+        addr7 = ipaddress.ip_network('192.0.2.1/32')
+        try:
+            list(addr6.address_exclude(addr7))
+        except ValueError:
+            self.fail('Unexpected ValueError raised')
 
     def testHash(self):
         self.assertEqual(hash(ipaddress.ip_interface('10.1.1.0/24')),