On July 30, Canonical announced that a vulnerability had been found in the Linux kernel packages, affecting the OMAP4 kernel of the Ubuntu 13.04 (Raring Ringtail) operating system.
According to Canonical, a format string vulnerability was found in the Broadcom B43 wireless driver for the Linux kernel. A local user could have exploited that flaw to gain administrative privileges.
The security flaws can be fixed if you upgrade your system to the linux-image-3.5.0-229-omap4 (3.5.0-229.42) package. Don't forget to reboot your computer after the upgrade!
ATTENTION: Due to an unavoidable ABI change, the kernel packages have a new version number, which will force you to reinstall and recompile all third-party kernel modules you might have installed. Moreover, if you use the linux-restricted-modules package, you have to update it as well to get modules that work with the new Linux kernel version.