diff --git a/src/iscidraddr.c b/src/iscidraddr.c
index 3d889bd..fbea53f 100644
--- a/src/iscidraddr.c
+++ b/src/iscidraddr.c
@@ -23,7 +23,7 @@ iscidraddr(const char *str)
     char addr[offset], cidr[3];
     char *c = (char*)&str[offset + 1];
     memcpy(addr, str, offset);
-    memcpy(cidr, c, 2);
+    memcpy(cidr, c, 3);
     addr[offset] = '\0';
     return isinetaddr(addr) && in_range(cidr, 0, 32);
   }
diff --git a/test/iscidraddr_test.c b/test/iscidraddr_test.c
index 95440fb..ed674e2 100644
--- a/test/iscidraddr_test.c
+++ b/test/iscidraddr_test.c
@@ -23,6 +23,7 @@ const char *invalid[] = {
   /* invalid cidr notation */
   "10.0.0.1/33", "127.0.0.1/64",
   "127.0.0.1/", "127.0.0.1/a",
+  "127.0.0.1/322",
   "/", "/123.","127/2",
   /* edge cases */
   "555555555555555555555555555555555555",