diff --git a/programs/x509/cert_app.c b/programs/x509/cert_app.c
index a45802c..b14b084 100644
--- a/programs/x509/cert_app.c
+++ b/programs/x509/cert_app.c
@@ -165,7 +165,7 @@
     memset(&cacrl, 0, sizeof(mbedtls_x509_crl));
 #endif
 
-    if (argc == 0) {
+    if (argc < 2) {
 usage:
         mbedtls_printf(USAGE);
         goto exit;