The COMCHANGEUSER command in MySQL 3.x before 3.23.54, and 4.x before 4.0.6, allows remote attackers to gain privileges via a brute force attack using a one-character password, which causes MySQL to only compare the provided password against the first character of the real password.

The COMCHANGEUSER command in MySQL 3.x before 3.23.54, and 4.x to 4.0.6, allows remote attackers to execute arbitrary code via a long response.

libmysqlclient client library in MySQL 3.x to 3.23.54, and 4.x to 4.0.6, does not properly verify length fields for certain responses in the (1) readrows or (2) readonerow routines, which allows remote attackers to cause a denial of service and possibly execute arbitrary code.