diff --git a/tools/cert_create/src/main.c b/tools/cert_create/src/main.c
index c87d988..c58f41d 100644
--- a/tools/cert_create/src/main.c
+++ b/tools/cert_create/src/main.c
@@ -428,9 +428,11 @@
 			 */
 			switch (ext->type) {
 			case EXT_TYPE_NVCOUNTER:
-				nvctr = atoi(ext->arg);
-				CHECK_NULL(cert_ext, ext_new_nvcounter(ext_nid,
+				if (ext->arg) {
+					nvctr = atoi(ext->arg);
+					CHECK_NULL(cert_ext, ext_new_nvcounter(ext_nid,
 						EXT_CRIT, nvctr));
+				}
 				break;
 			case EXT_TYPE_HASH:
 				if (ext->arg == NULL) {