diff --git a/cube/User/Src/tcpTest.c b/cube/User/Src/tcpTest.c
index bd51a9d..ca4ef33 100644
--- a/cube/User/Src/tcpTest.c
+++ b/cube/User/Src/tcpTest.c
@@ -83,6 +83,7 @@ void tcpTestHandler(void *handle) {
 
             if (res16 > 0) {
                 uint8_t *buf = (uint8_t*) malloc(res16);
+                memset(buf, 0, res16);
                 res32 = recv(TCPTEST_SOCK, buf, res16);
                 coloredMsg(LOG_YELLOW, "tth, recv returns 0x%02x", res32);
                 if (res32 > 0) {