14 DAY TRIAL // Canonical published details about the LibYAML vulnerability in its Ubuntu 13.10, Ubuntu 12.10, and Ubuntu 12.04 LTS operating systems.
According to the company, LibYAML could have been made to crash or run programs if it opened a specially crafted yaml document.
It has been discovered that LibYAML incorrectly handled certain large yaml documents. An attacker could have used this issue to cause LibYAML to crash, resulting in a denial of service, or possibly to execute arbitrary code.
For a more detailed description of the problems, you can see Canonical's security notification.
The flaws can be fixed if you upgrade your system(s) to the latest libyaml-0-2 package specific to each distribution. To apply the patch, run the Update Manager application.
In general, a standard system update will make all the necessary changes and you will have to restart all the applications that are using LibYAML.