diff --git a/library/x509_create.c b/library/x509_create.c
index fa66caeb5..863009651 100644
--- a/library/x509_create.c
+++ b/library/x509_create.c
@@ -73,7 +73,7 @@ static const x509_attr_descriptor_t x509_attrs[] =
     { ADD_STRLEN( "generationQualifier" ),      MBEDTLS_OID_AT_GENERATION_QUALIFIER, MBEDTLS_ASN1_UTF8_STRING },
     { ADD_STRLEN( "domainComponent" ),          MBEDTLS_OID_DOMAIN_COMPONENT,   MBEDTLS_ASN1_IA5_STRING },
     { ADD_STRLEN( "DC" ),                       MBEDTLS_OID_DOMAIN_COMPONENT,   MBEDTLS_ASN1_IA5_STRING },
-    { NULL, 0, NULL }
+    { NULL, 0, NULL, MBEDTLS_ASN1_NULL }
 };
 
 static const x509_attr_descriptor_t *x509_at_oid_from_name( const char *name, size_t name_len )