Several security issues were fixed in the kernel.
Vasily Averin discovered that the NFS Lock Manager (NLM) incorrectly handled unlock requests. A local attacker could exploit this to cause a denial of service. (CVE-2011-2491)
21 November 2011
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the kernel.
Vasily Averin discovered that the NFS Lock Manager (NLM) incorrectly handled unlock requests. A local attacker could exploit this to cause a denial of service. (CVE-2011-2491)
Robert Swiecki discovered that mapping extensions were incorrectly handled. A local attacker could exploit this to crash the system, leading to a denial of service. (CVE-2011-2496)
It was discovered that the wireless stack incorrectly verified SSID lengths. A local attacker could exploit this to cause a denial of service or gain root privileges. (CVE-2011-2517)
Ben Pfaff discovered that Classless Queuing Disciplines (qdiscs) were being incorrectly handled. A local attacker could exploit this to crash the system, leading to a denial of service. (CVE-2011-2525)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.
ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. If you use linux-restricted-modules, you have to update that package as well to get modules which work with the new kernel version. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-server, linux-powerpc), a standard system upgrade will automatically perform this as well.
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