Alerts This Week
Warning Icon 1 640
Alerts This Week
Warning Icon 1 640

Ubuntu 20.04 LTS USN-4915-1 Critical: Kernel Privilege Escalation

ubuntu
Calendar Grey April 15, 2021
Dist Ubuntu Esm H88
Uncover immediate remedies for Linux kernel security flaws in Ubuntu 20.04 LTS along with detailed upgrade guidelines.
Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

- linux-oem-5.6: Linux kernel for OEM systems

Details:

It was discovered that the overlayfs implementation in the Linux kernel did

not properly validate the application of file system capabilities with

respect to user namespaces. A local attacker could use this to gain

elevated privileges. (CVE-2021-3493)

Vincent Dehors discovered that the shiftfs file system in the Ubuntu Linux

kernel did not properly handle faults in copy_from_user() when passing

through ioctls to an underlying file system. A local attacker could use

this to cause a denial of service (memory exhaustion) or execute arbitrary

code. (CVE-2021-3492)

Topics%20covered

Topics Covered

security advisory denial of service privilege escalation Ubuntu kernel system update update instructions ubuntu elevated privileges linux-oem

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.04 LTS:
  linux-image-5.6.0-1054-oem      5.6.0-1054.58
  linux-image-oem-20.04           5.6.0.1054.50

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.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

References

https://ubuntu.com/security/notices/USN-4915-1

CVE-2021-3492, CVE-2021-3493

Severity
critical
Lowest
Low
Medium
High
Critical

April 15, 2021

Topics%20covered

Topics Covered

security advisory denial of service privilege escalation Ubuntu kernel system update update instructions ubuntu elevated privileges linux-oem

Package Information

https://launchpad.net/ubuntu/+source/linux-oem-5.6/5.6.0-1054.58

Get the latest News and Insights

Get the latest Linux and open source security news straight to your inbox.

Your message here