El Ubuntu kernel It is developed by Linus Torvalds and maintained by people you trust. On the other hand, companies like Canonical are in charge of maintaining their kernel by periodically releasing security updates. The last time they did it was on February 19, when they corrected at least 23 security flaws (difficult to know precisely because of the number of different reports they publish). Yesterday, the company that runs Mark Shuttleworth did it again.
This time they have fixed 11 security flaws, that at least. Those 11 are the number of vulnerabilities fixed that appear in the report USN-4300-1, where bugs that affect Ubuntu 19.10 and Ubuntu 18.04 LTS are detailed. Canonical has released 4 more reports: the USN-4301-1 detailing 8 bugs that affect Ubuntu 18.04 LTS, USN-4302-1 detailing 9 bugs that affect Ubuntu 18.04 LTS and Ubuntu 16.04 LTS, the USN-4303-1 which mentions a bug that affects Ubuntu 16.04 LTS and the USN-4303-2, which is the same as above, but for 14.04 ESM.
Update your Ubuntu and reboot to protect yourself from various vulnerabilities
In general, there are bug fixes that affect Canonical system versions from 14.04 to 19.10. Do not forget that only supported operating systems can receive these updates, which are the LTS versions since 2014, although 14.04 is in the Extended Security Maintenance phase, and Eoan Ermine, a release that will continue to be supported until July of this year. . Ubuntu 12.04, currently also in the ESM phase, is not mentioned in any bug, but Focal Fossa, in the development phase, does appear in the details of some of the vulnerabilities, such as the CVE-2019-3016. In any case, Focal Fossa will not reach its stable version until April 23.
New kernel versions are now available as an update on all supported operating systems. Once installed, the computer will have to be restarted for the changes to take effect.