diff --git a/src/tls.c b/src/tls.c
index a2f0e8782..0457eddd5 100644
--- a/src/tls.c
+++ b/src/tls.c
@@ -545,6 +545,7 @@ int MakeTlsMasterSecret(WOLFSSL* ssl)
         byte handshake_hash[HSHASH_SZ];
     #endif
 
+        XMEMSET(handshake_hash, 0, HSHASH_SZ);
         ret = BuildTlsHandshakeHash(ssl, handshake_hash, &hashSz);
         if (ret == 0) {
             ret = _MakeTlsExtendedMasterSecret(