diff --git a/tools/cert_create/src/ext.c b/tools/cert_create/src/ext.c
index 055ddbf..57fb47d 100644
--- a/tools/cert_create/src/ext.c
+++ b/tools/cert_create/src/ext.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -284,6 +284,7 @@
 	ex = ext_new(nid, crit, p, sz);
 
 	/* Clean up */
+	BIO_free(mem);
 	OPENSSL_free(p);
 
 	return ex;