Canonical published in a security notice details about ubuntu-release-upgrader vulnerability for its Ubuntu 12.10 (Quantal Quetzal) operating systems.
According to Canonical, ubuntu-release-upgrader would crash when attempting to upgrade it.
It has been discovered that ubuntu-release-upgrader failed when a user requested an upgrade to Ubuntu 13.04. This would prevent a user from migrating easily to Ubuntu 13.04 before the Ubuntu 12.10 support period ended.
For a more detailed description of the security problems, you can visit Canonical's security notification.
The security flaws can be fixed if you upgrade your system(s) to the latest ubuntu-release-upgrader-gtk package, specific to each distribution. To apply the update, run the Update Manager application.
In general, a standard system update will make all the necessary changes. A system restart will not be needed to implement the changes.