@z01zzz: Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
Trying to connect to a Raspberry Pi 3 (Bullseye), from a Windows 11 25H2 (build 26200.8655). I haven't used WinSCP in a while, but previously it was working (version 6.3.6). Both 6.3.6 and 6.5.6 are crashing now, every time when trying to connect.
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 6.5.6

Error message:
Invalid access to memory.

Stack trace:
(000023F5)NetworkSniffer.dll
(00EF78FE)
(00EF9976)
(00EF6720) __ExceptionHandler
(000B424F) ntdll.dll

(00EF7F69)
(00EF9543)
(00C96A3C) TSecureShell::Open
(00D32522) TTerminal::Open
(00C4B09B) TTerminalThread::TerminalOpenEvent
(00C45E18) TSignalThread::Execute
(000DF53B) Userinterface::C20_0
(00014D47) KERNEL32.DLL.BaseThreadInitThunk
(0006D129) ntdll.dll
(0006D0AC) ntdll.dll

(00EF7F69)
(00EF9543)
(00D326CA) TTerminal::Open
(00C4B09B) TTerminalThread::TerminalOpenEvent
(00C45E18) TSignalThread::Execute
(000DF53B) Userinterface::C20_0
(00014D47) KERNEL32.DLL.BaseThreadInitThunk
(0006D129) ntdll.dll
(0006D0AC) ntdll.dll

(00EF7F69)
(00EF9543)
(00D32CF2) TTerminal::Open
(00C4B09B) TTerminalThread::TerminalOpenEvent
(00C45E18) TSignalThread::Execute
(000DF53B) Userinterface::C20_0
(00014D47) KERNEL32.DLL.BaseThreadInitThunk
(0006D129) ntdll.dll
(0006D0AC) ntdll.dll

I know how to reproduce the problem or the problem happens frequently enough. I wish to be contacted by the WinSCP team to help resolving the problem.

Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.13.6

Error message:
Invalid access to memory.

Stack trace:
(00734601) TSecureShell::Open
(008BF022) C5105_0
(008C108A) ____ExceptionHandler
(008BDE44) __ExceptionHandler
(0003EF0E) ntdll.dll.ZwWow64CallFunction64
(0003F68A) ntdll.dll.KiUserExceptionDispatcher
(007B7237) TTerminal::Open
(006F3CB3) TTerminalThread::TerminalOpenEvent
(006EECC8) TSignalThread::Execute
(000A3D57) Userinterface::C20_0
(00016C02) KERNEL32.DLL.BaseThreadInitThunk
(00059D8D) ntdll.dll
(00059D55) ntdll.dll

(008BF68D) C5105_0
(008C0C67) _ReThrowException
(007B739C) TTerminal::Open
(006F3CB3) TTerminalThread::TerminalOpenEvent
(006EECC8) TSignalThread::Execute
(000A3D57) Userinterface::C20_0
(00016C02) KERNEL32.DLL.BaseThreadInitThunk
(00059D8D) ntdll.dll
(00059D55) ntdll.dll

(008BF68D) C5105_0
(008C0C67) _ReThrowException
(007B7959) TTerminal::Open
(006F3CB3) TTerminalThread::TerminalOpenEvent
(006EECC8) TSignalThread::Execute
(000A3D57) Userinterface::C20_0
(00016C02) KERNEL32.DLL.BaseThreadInitThunk
(00059D8D) ntdll.dll
(00059D55) ntdll.dll

I know how to reproduce the problem or the problem happens frequently enough. I wish to be contacted by the WinSCP team to help resolving the problem.