diff --git a/library/ssl_tls.c b/library/ssl_tls.c index 6a44145d7e..bca5b403cb 100644 --- a/library/ssl_tls.c +++ b/library/ssl_tls.c @@ -3656,6 +3656,14 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl ) ( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER && ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_HELLO ) ) ) { + if( recv_msg_seq > ssl->handshake->in_msg_seq ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "received future handshake message of sequence number %u (next %u)", + recv_msg_seq, + ssl->handshake->in_msg_seq ) ); + return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); + } + /* Retransmit only on last message from previous flight, to avoid * too many retransmissions. * Besides, No sane server ever retransmits HelloVerifyRequest */