NoMachine client 6.12.3 suddenly closes when connecting by NX protocol

Added On: 2020-10-05 Last Modified: 2020-10-05
ID: TR10R09852 Status: Open
Severity: Serious Products:
Target: Platform: All Windows Platforms

NoMachine client v. 6.12.3 for Windows suddenly closes during the login phase when connecting by NX protocol due to an attempt to free memory at invalid address. When this happens, the nxtrace.log reports: 

 
Module: C:\Program Files (x86)\NoMachine Enterprise Client\bin\nxplayer.bin pid 7240
 
Thread: 6156 exception 0xc0000005, 'Access violation'
 
In: C:\WINDOWS\SYSTEM32\ntdll.dll at 0x77414638
 
Error: Invalid read from address 0x0
 
#0  0x77414638 ntdll.dll(RtlFreeHeap)
#1  0x774134a8 ntdll.dll(RtlFreeHeap)
#2  0x75bc7815 msvcrt.dll(free)
#3  0x6486e72e libssh.dll(_b64_pton)
#4  0x66fd78f6 libnx.dll(ZN8RunnabledlEPv)
#5  0x6487345f libssh.dll(nxgss_release)
#6  0x63e06eb1 libnxd.dll(ZN12DaemonWriterD0Ev)
#7  0x6703996e libnx.dll(ZN8Kerberos7releaseEv)
#8  0x63e0cdf3 libnxd.dll(ZN11DaemonLogin11finishLoginEv)
#9  0x63e143f6 libnxd.dll(ZN11DaemonLogin8runStageEv)
#10 0x774102b5 ntdll.dll(RtlAllocateHeap)
#11 0x774134a8 ntdll.dll(RtlFreeHeap)
#12 0x75bc7815 msvcrt.dll(free)
#13 0x66f94602 libnx.dll(Z13StringToLowerPc)
#14 0x63e0edf0 libnxd.dll(ZN11DaemonLogin18parseRemoteStoringERPcRi)
#15 0x63e0eee9 libnxd.dll(ZN11DaemonLogin17parseRemotePromptERPci)
#16 0x63e14af3 libnxd.dll(ZN11DaemonLogin11dataMessageEPci)
#17 0x66ffc8be libnx.dll(ZN6Reader12parseMessageERiS0_S0_)
#18 0x66ffd210 libnx.dll(ZN6Reader14consumeMessageERi)
#19 0x66ffd67e libnx.dll(ZN6Reader11readMessageEv)