The COM_CHANGE_USER 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.

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) read_rows or (2) read_one_row routines, which allows remote attackers to cause a denial of service and possibly execute arbitrary code.

The COM_CHANGE_USER 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.

Signed integer vulnerability in the COM_TABLE_DUMP package for MySQL 3.23.x before 3.23.54 allows remote attackers to cause a denial of service (crash or hang) in mysqld by causing large negative integers to be provided to a memcpy call.

MySQL 3.22 allows remote attackers to bypass password authentication and access a database via a short check string.

MySQL allows local users to modify passwords for arbitrary MySQL users via the GRANT privilege.