--- a/ykcs11/tests/ykcs11_tests_util.c
+++ b/ykcs11/tests/ykcs11_tests_util.c
@@ -281,7 +281,7 @@ void test_digest_func(CK_FUNCTION_LIST_PTR funcs, CK_SESSION_HANDLE session, CK_
   CK_BYTE     digest_update[128] = {0};
   CK_ULONG    digest_update_len;
   CK_BYTE     hdata[128] = {0};
-  CK_ULONG    hdata_len;
+  CK_ULONG    hdata_len = 0;

   CK_MECHANISM mech = {mech_type, NULL, 0};