In the first week of April Ubuntu issued security updates to address vulnerabilities responsibly disclosed (defined) in the Ubuntu kernel (defined). Each vulnerability addressed was assigned a separate CVE identifier (defined).
Why Should These Issues Be Considered Important?
While no severities were assigned by Ubuntu to these issues any issue within the kernel can be consider high to critical severity (if it is remotely exploitable) since if control of the kernel can be obtained an attacker can then use that control to carry out any action of their choice. Ubuntu does however mention that the most severe of these issues can potential lead to remote code execution (the ability for an attacker to remotely carry out any action of their choice on your Ubuntu device) while the remainder can lead to denial of service conditions (defined).
The types of vulnerabilities addressed are varied and range from use-after-free (defined) vulnerabilities to timing side channel attacks (defined, in this case exploiting the timing within the Linux Extended Verification Module (EVM)) to a buffer overflow (defined) and incorrect file descriptor handling (defined).
How Can I Protect Myself From These Issues?
Within Ubuntu’s security advisory they provide the steps to download the appropriate updates for the version of Ubuntu that you are using. In addition, a system reboot is required for these updates to take effect.
In addition, 3 recent security advisories listed below were also made by available by Ubuntu, please ensure that you have followed the steps within each to ensure that you are protected from these vulnerabilities: