Parallels have reported the following security vulnerability.  You can follow their instructions to update your Plesk instance.  Or please just pop in a support ticket and we can perform the update for you.

Parallel's notification:

Dear Parallels Plesk Panel User:

Please read this message in its entirety and take the recommended actions.

Parallels has been informed of a SQL injection security vulnerability in some older versions of Plesk. This vulnerability is considered critical in nature and customers are advised take action quickly.

A patch has been released to resolve this vulnerability. Based on the version and operating system of Plesk you use, please follow the instructions below.

Linux

Plesk 10 - Update to Plesk 10.3.1 MicroUpdate #6 or later.
Update Instructions: http://download1.parallels.com/Plesk/PP10/10.4/Doc/en-US/online/plesk-installation-upgrade-guide/index.htm?fileName=65789.htm

If possible, it is recommended to update all the way to Plesk 10.4.4 to provide the most stable user experience.

Plesk 9 - Update to Plesk 9.5.4 MicroUpdate #11 or later
Update Instructions: http://download1.parallels.com/Plesk/PPP9/Doc/en-US/plesk-9.5-unix-installation-guide/index.htm?fileName=18514.htm

Plesk 8 - Update to Plesk 8.6.0 MicroUpdate #2 or later
Update Instructions: http://download1.parallels.com/Plesk/Plesk8.6/Doc/en-US/plesk-8.6-unix-installation-guide/index.htm?fileName=18514.htm

If you are already at or above the Version and MicroUpdate levels indicated above - you are already protected from this vulnerability.

Parallels takes the security of our customers very seriously and urges you to act quickly by applying these patches.

Thanks,

- The Parallels Plesk Panel Team