Just upgrade the operating system in order to fix any issues
Canonical published details in a security notice about an Apache XML Security for a Java vulnerability in its Ubuntu 10.04 LTS (Lucid Lynx) operating system.According to the company, Apache XML Security for Java could be tricked into validating spoofed signatures.
It has been discovered that Apache XML Security for Java incorrectly validated CanonicalizationMethod parameters. An attacker could have used use this flaw to spoof XML signatures.
For a more detailed description of the security problems, you can see Canonical's security notification.
The security flaws can be fixed if you upgrade your system(s) to the latest libxml-security-java 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 and you won't need to restart the system.