The use of a weak cryptographic key pair in the signature verification process in WPS Office (Kingsoft) on Windows allows an attacker who successfully recovered the private key to sign components. As older versions of WPS Office did not validate the update server's certificate, an Adversary-In-The-Middle attack was possible allowing updates to be hijacked.
The product stores or transmits sensitive data using an encryption scheme that is theoretically sound, but is not strong enough for the level of protection required.