MySQL is a multi-user, multi-threaded SQL database server. It consists of the MySQL server daemon (mysqld) and many client programs and libraries.
Multiple flaws were discovered in the way MySQL handled symbolic links to tables created using the DATA DIRECTORY and INDEX DIRECTORY directives in CREATE TABLE statements. An attacker with CREATE and DROP table privileges and shell access to the database server could use these flaws to escalate their database privileges, or gain access to tables created by other database users. (CVE-2008-4098, CVE-2009-4030)
Note: Due to the security risks and previous security issues related to the use of the DATA DIRECTORY and INDEX DIRECTORY directives, users not depending on this feature should consider disabling it by adding "symbolic-links=0" to the "[mysqld]" section of the "my.cnf" configuration file. In this update, an example of such a configuration was added to the default "my.cnf" file.
An insufficient HTML entities quoting flaw was found in the mysql command line client's HTML output mode. If an attacker was able to inject arbitrary HTML tags into data stored in a MySQL database, which was later retrieved using the mysql command line client and its HTML output mode, they could perform a cross-site scripting (XSS) attack against victims viewing the HTML output in a web browser. (CVE-2008-4456)
Multiple format string flaws were found in the way the MySQL server logged user commands when creating and deleting databases. A remote, authenticated attacker with permissions to CREATE and DROP databases could use these flaws to formulate a specially-crafted SQL command that would cause a temporary denial of service (open connections to mysqld are terminated). (CVE-2009-2446)
Note: To exploit the CVE-2009-2446 flaws, the general query log (the mysqld "--log" command line option or the "log" option in "my.cnf") must be enabled. This logging is not enabled by default.
All MySQL users are advised to upgrade to these updated packages, which contain backported patches to resolve these issues. After installing this update, the MySQL server daemon (mysqld) will be restarted automatically.