A path traversal vulnerability exists in the file dropoff functionality of ZendTo versions 6.15-7 and prior. This could allow a remote, authenticated attacker to retrieve the files of other ZendTo users, retrieve files on the host system, or cause a denial of service.

A type confusion vulnerability in lib/NSSAuthenticator.php in ZendTo before v5.04-7 allows remote attackers to bypass authentication for users with passwords stored as MD5 hashes that can be interpreted as numbers. A solution requires moving from MD5 to bcrypt.

An OS command injection vulnerability in lib/NSSDropoff.php in ZendTo 5.24-3 through 6.x before 6.10-7 allows unauthenticated remote attackers to execute arbitrary commands via shell metacharacters in the tmpname parameter when dropping off a file via a POST /dropoff request.