diff --git a/sys/netlink/netlink_generic.c b/sys/netlink/netlink_generic.c
--- a/sys/netlink/netlink_generic.c
+++ b/sys/netlink/netlink_generic.c
@@ -67,7 +67,8 @@
 		return (ENOTSUP);
 	}
 
-	if (__predict_false(hdr->nlmsg_len < sizeof(hdr) + GENL_HDRLEN)) {
+	if (__predict_false(hdr->nlmsg_len < sizeof(struct nlmsghdr) +
+	    GENL_HDRLEN)) {
 		NLP_LOG(LOG_DEBUG, nlp, "invalid message size: %d", hdr->nlmsg_len);
 		return (EINVAL);
 	}