diff --git a/apps/asn1pars.c b/apps/asn1pars.c
index bde61d02d1..305cdfc6af 100644
--- a/apps/asn1pars.c
+++ b/apps/asn1pars.c
@@ -408,6 +408,7 @@ static int do_generate(BIO *bio, char *genstr, char *genconf, BUF_MEM *buf)
 
 	atyp = ASN1_generate_nconf(genstr, cnf);
 	NCONF_free(cnf);
+	cnf = NULL;
 
 	if (!atyp)
 		return -1;