diff --git a/lib/prefix.c b/lib/prefix.c
index 3e4ca16..aeb627b 100644
--- a/lib/prefix.c
+++ b/lib/prefix.c
@@ -566,7 +566,7 @@
     {
       int plen;
 
-      cp = XMALLOC (0, (pnt - str) + 1);
+      cp = XMALLOC (MTYPE_TMP, (pnt - str) + 1);
       strncpy (cp, str, pnt - str);
       *(cp + (pnt - str)) = '\0';
       ret = inet_pton (AF_INET6, cp, &p->prefix);