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Ubuntu Security Notice USN-5572-1
August 18, 2022

linux-aws vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems

Details:

Roger Pau Monné discovered that the Xen virtual block driver in the 
Linux kernel did not properly initialize memory pages to be used for 
shared communication with the backend. A local attacker could use this 
to expose sensitive information (guest kernel memory). (CVE-2022-26365)

Roger Pau Monné discovered that the Xen paravirtualization frontend in 
the Linux kernel did not properly initialize memory pages to be used for 
shared communication with the backend. A local attacker could use this 
to expose sensitive information (guest kernel memory). (CVE-2022-33740)

It was discovered that the Xen paravirtualization frontend in the Linux
kernel incorrectly shared unrelated data when communicating with certain
backends. A local attacker could use this to cause a denial of service
(guest crash) or expose sensitive information (guest kernel memory).
(CVE-2022-33741)

Update instructions:

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

Ubuntu 16.04 ESM:
   linux-image-4.4.0-1148-aws      4.4.0-1148.163
   linux-image-aws                 4.4.0.1148.152

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-5572-1
   CVE-2022-26365, CVE-2022-33740, CVE-2022-33741