diff --git a/lib/dns/opensslrsa_link.c b/lib/dns/opensslrsa_link.c
index 64287854cc..ce40ab1c31 100644
--- a/lib/dns/opensslrsa_link.c
+++ b/lib/dns/opensslrsa_link.c
@@ -692,6 +692,9 @@ opensslrsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
 	e = BN_bin2bn(r.base, e_bytes, NULL);
 	isc_region_consume(&r, e_bytes);
 	n = BN_bin2bn(r.base, r.length, NULL);
+	if (e == NULL || n == NULL) {
+		DST_RET(ISC_R_NOMEMORY);
+	}
 
 	key->key_size = BN_num_bits(n);