1. Ubuntu Security Notices
  2. USN-4947-1

USN-4947-1: Linux kernel (OEM) vulnerabilities

Publication date

11 May 2021

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

Details

Kiyin (尹亮) discovered that the x25 implementation in the Linux kernel
contained overflows when handling addresses from user space. A local
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2020-35519)

It was discovered that the fastrpc driver in the Linux kernel did not
prevent user space applications from sending kernel RPC messages. A local
attacker could possibly use this to gain elevated privileges.
(CVE-2021-28375)

It was discovered that the TIPC protocol implementation in the Linux kernel
did not properly validate passed encryption key sizes. A local attacker
could use this to cause a denial of service (system crash).
(CVE-2021-29646)

It was discovered that a race condition existed in the netfilter subsystem
of the Linux kernel when...

Kiyin (尹亮) discovered that the x25 implementation in the Linux kernel
contained overflows when handling addresses from user space. A local
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2020-35519)

It was discovered that the fastrpc driver in the Linux kernel did not
prevent user space applications from sending kernel RPC messages. A local
attacker could possibly use this to gain elevated privileges.
(CVE-2021-28375)

It was discovered that the TIPC protocol implementation in the Linux kernel
did not properly validate passed encryption key sizes. A local attacker
could use this to cause a denial of service (system crash).
(CVE-2021-29646)

It was discovered that a race condition existed in the netfilter subsystem
of the Linux kernel when replacing tables. A local attacker could use this
to cause a denial of service (system crash). (CVE-2021-29650)

Arnd Bergmann discovered that the video4linux subsystem in the Linux kernel
did not properly deallocate memory in some situations. A local attacker
could use this to cause a denial of service (memory exhaustion).
(CVE-2021-30002)

Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

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.

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

Ubuntu Release Package Version
20.04 focal linux-image-5.6.0-1056-oem –  5.6.0-1056.60
linux-image-oem-20.04 –  5.6.0.1056.52

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Get Ubuntu Pro

References

Have additional questions?

Talk to a member of the team ›