An issue was discovered in heinekingmedia StashCat through 1.7.5 for Android, through 0.0.80w for Web, and through 0.0.86 for Desktop. It uses RSA to exchange a secret for symmetric encryption of messages. However, the private RSA key is not only stored on the client but transmitted to the backend, too. Moreover, the key to decrypt the private key is composed of the first 32 bytes of the SHA-512 hash of the user password. But this hash is stored on the backend, too. Therefore, everyone with access to the backend database can read the transmitted secret for symmetric encryption, hence can read the communication.