On October 4th, in a security notice Canonical published details about some Python 2.7 vulnerabilities affecting its Ubuntu 11.10, Ubuntu 11.04, and Ubuntu 10.04 LTS operating systems.
According to Canonical, several security issues were fixed in Python 2.6. Multiple vulnerabilities have been unidentified and repaired. A local attacker with write access to the current working directory, could have used this exploit to execute arbitrary, to cause a denial of service via application crash, and even obtain access to CGI script source files.
If you want to see what had been fixed, check out the appropriate package links: CVE-2008-5983, CVE-2010-1634, CVE-2010-2089, CVE-2010-3493, CVE-2011-1015, CVE-2011-1521, CVE-2011-4940, CVE-2011-4944, CVE-2012-0845, and CVE-2012-1150.
The security flaws can be fixed if you upgrade your system(s) to the latest python2.6 and python2.6-minimal, specific to each operating system. To apply the update, run the Update Manager application.
In general, a standard system update will make all the necessary changes. A system restart won't be necessary to implement the changes.