PuTTY - old-style scp downloads may allow remote code execution

Simon G. Tatham reports:

Many versions of PSCP prior to 0.67 have a stack corruption
vulnerability in their treatment of the ‘sink’ direction (i.e.
downloading from server to client) of the old-style SCP protocol.

In order for this vulnerability to be exploited, the user must
connect to a malicious server and attempt to download any file.[…]
you can work around it in a vulnerable PSCP by using the -sftp
option to force the use of the newer SFTP protocol, provided your
server supports that protocol.