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Ubuntu Security Notice USN-5652-1
October 03, 2022

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

- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-azure: Linux kernel for Microsoft Azure Cloud systems

Details:

It was discovered that the framebuffer driver on the Linux kernel did not
verify size limits when changing font or screen size, leading to an out-of-
bounds write. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2021-33655)

Domingo Dirutigliano and Nicola Guerrera discovered that the netfilter
subsystem in the Linux kernel did not properly handle rules that truncated
packets below the packet header size. When such rules are in place, a
remote attacker could possibly use this to cause a denial of service
(system crash). (CVE-2022-36946)

Update instructions:

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

Ubuntu 16.04 ESM:
   linux-image-4.15.0-1151-azure   4.15.0-1151.166~16.04.1
   linux-image-azure               4.15.0.1151.138

Ubuntu 14.04 ESM:
   linux-image-4.15.0-1151-azure   4.15.0-1151.166~14.04.1
   linux-image-azure               4.15.0.1151.120

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-5652-1
   CVE-2021-33655, CVE-2022-36946