MySQL 4.x before 4.0.21, and 3.x before 3.23.49, allows attackers to cause a denial of service (crash or hang) via multiple threads that simultaneously alter MERGE table UNIONs.

mysqlbug in MySQL allows local users to overwrite arbitrary files via a symlink attack on the failed-mysql-bugreport temporary file.

MySQL 4.0.23 and earlier, and 4.1.x up to 4.1.10, uses predictable file names when creating temporary tables, which allows local users with CREATE TEMPORARY TABLE privileges to overwrite arbitrary files via a symlink attack.

MySQL 4.1 before 4.1.21 and 5.0 before 5.0.24 allows a local user to access a table through a previously created MERGE table, even after the user's privileges are revoked for the original table, which might violate intended security policy.

MySQL before 4.1.21, 5.0 before 5.0.25, and 5.1 before 5.1.12, when run on case-sensitive filesystems, allows remote authenticated users to create or access a database when the database name differs only in case from a database for which they have permissions.