PuTTY through 0.75 proceeds with establishing an SSH session even if it has never sent a substantive authentication response. This makes it easier for an attacker-controlled SSH server to present a later spoofed authentication prompt (that the attacker can use to capture credential data, and use that data for purposes that are undesired by the client user).
The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Putty | Putty | * | 0.75 (including) |
| Putty | Ubuntu | bionic | * |
| Putty | Ubuntu | groovy | * |
| Putty | Ubuntu | hirsute | * |
| Putty | Ubuntu | impish | * |
| Putty | Ubuntu | kinetic | * |
| Putty | Ubuntu | trusty | * |
| Putty | Ubuntu | upstream | * |
| Putty | Ubuntu | xenial | * |