diff --git a/lib/dns/rdata/generic/nxt_30.c b/lib/dns/rdata/generic/nxt_30.c
index 9d39f22d21..2655861a92 100644
--- a/lib/dns/rdata/generic/nxt_30.c
+++ b/lib/dns/rdata/generic/nxt_30.c
@@ -148,8 +148,8 @@ fromwire_nxt(ARGS_FROMWIRE) {
 	RETERR(dns_name_fromwire(&name, source, dctx, options, target));
 
 	isc_buffer_activeregion(source, &sr);
-	if (sr.length > 0 && (sr.base[0] & 0x80) == 0 &&
-	    ((sr.length > 16) || sr.base[sr.length - 1] == 0))
+	if (sr.length > 0 && ((sr.base[0] & 0x80) != 0 || sr.length > 16 ||
+			      sr.base[sr.length - 1] == 0))
 	{
 		return (DNS_R_BADBITMAP);
 	}