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Ubuntu Security Notice USN-5015-1
July 20, 2021

linux-oem-5.10 vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-oem-5.10: Linux kernel for OEM systems

Details:

It was discovered that the virtual file system implementation in the Linux
kernel contained an unsigned to signed integer conversion error. A local
attacker could use this to cause a denial of service (system crash) or
execute arbitrary code. (CVE-2021-33909)

Michael Brown discovered that the Xen netback driver in the Linux kernel
did not properly handle malformed packets from a network PV frontend,
leading to a use-after-free vulnerability. An attacker in a guest VM could
use this to cause a denial of service or possibly execute arbitrary code.
(CVE-2021-28691)

It was discovered that the bluetooth subsystem in the Linux kernel did not
properly handle HCI device initialization failure, leading to a double-free
vulnerability. An attacker could use this to cause a denial of service or
possibly execute arbitrary code. (CVE-2021-3564)

It was discovered that the bluetooth subsystem in the Linux kernel did not
properly handle HCI device detach events, leading to a use-after-free
vulnerability. An attacker could use this to cause a denial of service or
possibly execute arbitrary code. (CVE-2021-3573)

It was discovered that the NFC implementation in the Linux kernel did not
properly handle failed connect events leading to a NULL pointer
dereference. A local attacker could use this to cause a denial of service.
(CVE-2021-3587)

Update instructions:

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

Ubuntu 20.04 LTS:
  linux-image-5.10.0-1038-oem     5.10.0-1038.40
  linux-image-oem-20.04           5.10.0.1038.40
  linux-image-oem-20.04b          5.10.0.1038.40

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-5015-1
  CVE-2021-28691, CVE-2021-33909, CVE-2021-3564, CVE-2021-3573,
  CVE-2021-3587

Package Information:
  https://launchpad.net/ubuntu/+source/linux-oem-5.10/5.10.0-1038.40