diff --git a/src/network/networkd-address.c b/src/network/networkd-address.c
index 8e6d913cd5..b94e0d3af0 100644
--- a/src/network/networkd-address.c
+++ b/src/network/networkd-address.c
@@ -373,6 +373,9 @@ static void address_hash_func(const Address *a, struct siphash *state) {
         }
         case AF_INET6:
                 siphash24_compress(&a->in_addr.in6, sizeof(a->in_addr.in6), state);
+
+                if (in6_addr_is_null(&a->in_addr.in6))
+                        siphash24_compress(&a->prefixlen, sizeof(a->prefixlen), state);
                 break;
 
         default:
@@ -407,7 +410,16 @@ static int address_compare_func(const Address *a1, const Address *a2) {
         }
         case AF_INET6:
                 /* See kernel's ipv6_get_ifaddr() in net/ipv6/addrconf.c */
-                return memcmp(&a1->in_addr.in6, &a2->in_addr.in6, sizeof(a1->in_addr.in6));
+                r = memcmp(&a1->in_addr.in6, &a2->in_addr.in6, sizeof(a1->in_addr.in6));
+                if (r != 0)
+                        return r;
+
+                /* To distinguish IPv6 null addresses with different prefixlen, e.g. ::48 vs ::64, let's
+                 * compare the prefix length. */
+                if (in6_addr_is_null(&a1->in_addr.in6))
+                        r = CMP(a1->prefixlen, a2->prefixlen);
+
+                return r;
 
         default:
                 /* treat any other address family as AF_UNSPEC */