On January 30, Canonical announced in a security notice that a new Linux kernel update was available for its Ubuntu 13.10 (Saucy Salamander) operating system, fixing a security issue found recently in the Linux kernel packages.
It was discovered that pageexec reported a bug in the Linux kernel's recvmsg syscall when it was called from code using the x32 ABI, which could allow an unprivileged local user to cause a DoS (Denial of Service) attack or gain root privileges.
More information about this Linux kernel security issue can be found in the CVE-2014-0038 reference and it affects other Linux operating systems as well.
The security flaw can be fixed if you upgrade your Ubuntu 13.10 system(s) to the linux-image-3.11.0-15 (3.11.0-15.25) package(s). To apply the update, run the Update Manager application and install all the available updates, or read the instructions provided by Canonical at https://wiki.ubuntu.com/Security/Upgrades.
Don't forget to reboot your computer after the upgrade!