14 DAY TRIAL // Canonical published in a security notice details about a curl vulnerability in its Ubuntu 13.10, Ubuntu 13.04, Ubuntu 12.10, and Ubuntu 12.04 LTS operating systems.
According to the company, fraudulent security certificates could have allowed sensitive information to be exposed when accessing the Internet.
It has been discovered that libcurl incorrectly verified CN and SAN name fields when digital signature verification was disabled in the GnuTLS backend.
When libcurl was being used in this uncommon way by specific applications, an attacker could have exploited this to perform a man-in-the-middle attack and to view sensitive information or alter encrypted communications.
For a more detailed description of the problems, you can see Canonical's security notification.
The security flaws can be fixed if you upgrade your system(s) to the latest libcurl3-gnutls 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.