Multiple integer overflows in the (1) sftp_pkt_getstring and (2) fxp_readdir_recv functions in the PSFTP and PSCP clients for PuTTY 0.56, and possibly earlier versions, allow remote malicious web sites to execute arbitrary code via SFTP responses that corrupt the heap after insufficient memory has been allocated.

Potential recycling of random numbers used in cryptography exists within PuTTY before 0.71.

In PuTTY versions before 0.71 on Unix, a remotely triggerable buffer overflow exists in any kind of server-to-client forwarding.

PuTTY before 0.73 on Windows improperly opens port-forwarding listening sockets, which allows attackers to listen on the same port to steal an incoming connection.

The ssh_agent_channel_data function in PuTTY before 0.68 allows remote attackers to have unspecified impact via a large length value in an agent protocol message and leveraging the ability to connect to the Unix-domain socket representing the forwarded agent connection, which trigger a buffer overflow.

The PuTTY terminal emulator 0.53 allows attackers to modify the window title via a certain character escape sequence and then insert it back to the command line in the user's terminal, e.g. when the user views a file containing the malicious sequence, which could allow the attacker to execute arbitrary commands.