diff --git a/lib/hx509/test_soft_pkcs11.c b/lib/hx509/test_soft_pkcs11.c
index 0587b28a3..fcf45f0b9 100644
--- a/lib/hx509/test_soft_pkcs11.c
+++ b/lib/hx509/test_soft_pkcs11.c
@@ -213,7 +213,7 @@ main(int argc, char **argv)
 	    return 1;
 	}
 
-	if (memcmp(sighash, outdata, strlen(sighash)) != 0)
+	if (ct_memcmp(sighash, outdata, strlen(sighash)) != 0)
 	    return 1;
     }
 #endif