diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index 75eda1d..89fb403 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -2236,8 +2236,8 @@
 void ssl_mock_sanity( )
 {
     enum { MSGLEN = 105 };
-    unsigned char message[MSGLEN];
-    unsigned char received[MSGLEN];
+    unsigned char message[MSGLEN] = { 0 };
+    unsigned char received[MSGLEN] = { 0 };
     mbedtls_mock_socket socket;
 
     mbedtls_mock_socket_init( &socket );