On February 14, Canonical published in a security notice details about Qt vulnerabilities for its Ubuntu 12.10, Ubuntu 12.04 LTS, Ubuntu 11.10 and Ubuntu 10.04 LTS (Lucid Lynx) operating systems.
According to Canonical, several security issues were fixed in Qt. For example, Richard J. Moore and Peter Hartmann discovered that Qt allowed redirecting requests from http to file schemes.
If an attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to view sensitive information. This issue only affected Ubuntu 11.10, Ubuntu 12.04 LTS, and Ubuntu 12.10.
For a more detailed description of the security problems, you can visit Canonical's security notification
Users can simply fix the security flaws by upgrading the operating systems to the latest libqt4-core and libqt4-network packages, specific to each distribution.
A normal system update, executed with the Update Manager, will implement all the necessary changes. You need to restart your session to make all the necessary changes.