diff --git a/hostfile.c b/hostfile.c
index 7af47adf3..a4a355972 100644
--- a/hostfile.c
+++ b/hostfile.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: hostfile.c,v 1.78 2020/02/26 13:40:09 jsg Exp $ */
+/* $OpenBSD: hostfile.c,v 1.79 2020/03/06 18:25:12 markus Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -312,7 +312,7 @@ check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k)
 			continue;
 		if (sshkey_equal_public(k, hostkeys->entries[i].key))
 			return -1;
-		if (is_cert &&
+		if (is_cert && k != NULL &&
 		    sshkey_equal_public(k->cert->signature_key,
 		    hostkeys->entries[i].key))
 			return -1;