Several security issues were fixed in the kernel.
Sasha Levin discovered a flaw in the permission checking for device assignments requested via the kvm ioctl in the Linux kernel. A local user could use this flaw to crash the system causing a denial of service. (CVE-2011-4347)
24 April 2012
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the kernel.
Sasha Levin discovered a flaw in the permission checking for device assignments requested via the kvm ioctl in the Linux kernel. A local user could use this flaw to crash the system causing a denial of service. (CVE-2011-4347)
Stephan Bärwolf discovered a flaw in the KVM (kernel-based virtual machine) subsystem of the Linux kernel. A local unprivileged user can crash use this flaw to crash VMs causing a deny of service. (CVE-2012-0045)
A flaw was discovered in the Linux kernel’s cifs file system. An unprivileged local user could exploit this flaw to crash the system leading to a denial of service. (CVE-2012-1090)
H. Peter Anvin reported a flaw in the Linux kernel that could crash the system. A local user could exploit this flaw to crash the system. (CVE-2012-1097)
Tetsuo Handa reported a flaw in the OOM (out of memory) killer of the Linux kernel. A local unprivileged user can exploit this flaw to cause system unstability and denial of services. (CVE-2012-4398)
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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