On April 18, Canonical published, in a security, notice details about IcedTea-Web vulnerabilities for its Ubuntu 12.10, Ubuntu 12.04 LTS, Ubuntu 11.10, and Ubuntu 10.04 LTS operating systems.
According to Canonical, two security issues have been fixed in IcedTea-Web.
For example, it was discovered that IcedTea-Web would use the same classloader for applets from different domains. A remote attacker could exploit this problem to expose sensitive information or potentially manipulate applets from other domains.
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 icedtea-netx 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 necessary to implement the changes.