The following updates has been released for Ubuntu Linux:

USN-3579-1: LibreOffice vulnerability
USN-3580-1: Linux kernel vulnerabilities

USN-3579-1: LibreOffice vulnerability

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Ubuntu Security Notice USN-3579-1
February 21, 2018

libreoffice vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 17.10
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

LibreOffice would allow unintended access to files over the network.

Software Description:
- libreoffice: Office productivity suite

Details:

It was discovered that =WEBSERVICE calls in a document could be used to
read arbitrary files. If a user were tricked in to opening a specially
crafted document, a remote attacker could exploit this to obtain sensitive
information. (CVE-2018-6871)

Update instructions:

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

Ubuntu 17.10:
libreoffice-core 1:5.4.5-0ubuntu0.17.10.1

Ubuntu 16.04 LTS:
libreoffice-core 1:5.1.6~rc2-0ubuntu1~xenial3

Ubuntu 14.04 LTS:
libreoffice-core 1:4.2.8-0ubuntu5.3

After a standard system update you need to restart LibreOffice to make
all the necessary changes.

References:
https://www.ubuntu.com/usn/usn-3579-1
CVE-2018-6871

Package Information:
https://launchpad.net/ubuntu/+source/libreoffice/1:5.4.5-0ubuntu0.17.10.1
https://launchpad.net/ubuntu/+source/libreoffice/1:5.1.6~rc2-0ubuntu1~xenial3
https://launchpad.net/ubuntu/+source/libreoffice/1:4.2.8-0ubuntu5.3

USN-3580-1: Linux kernel vulnerabilities

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Ubuntu Security Notice USN-3580-1
February 22, 2018

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

- Ubuntu 12.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel

Details:

Jann Horn discovered that microprocessors utilizing speculative execution
and branch prediction may allow unauthorized memory reads via sidechannel
attacks. This flaw is known as Spectre. A local attacker could use this to
expose sensitive information, including kernel memory.

Update instructions:

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

Ubuntu 12.04 ESM:
linux-image-3.2.0-133-generic 3.2.0-133.179
linux-image-3.2.0-133-generic-pae 3.2.0-133.179
linux-image-generic 3.2.0.133.148
linux-image-generic-pae 3.2.0.133.148

Please note that fully mitigating CVE-2017-5715 (Spectre Variant 2)
requires corresponding processor microcode/firmware updates or,
in virtual environments, hypervisor updates. On i386 and amd64
architectures, the IBRS and IBPB features are required to enable the
kernel mitigations. Ubuntu is working with Intel and AMD to provide
future microcode updates that implement IBRS and IBPB as they are made
available. Ubuntu users with a processor from a different vendor should
contact the vendor to identify necessary firmware updates. Ubuntu
will provide corresponding QEMU updates in the future for users of
self-hosted virtual environments in coordination with upstream QEMU.
Ubuntu users in cloud environments should contact the cloud provider
to confirm that the hypervisor has been updated to expose the new
CPU features to virtual machines.

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

References:
https://www.ubuntu.com/usn/usn-3580-1
https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SpectreAndMeltdown
CVE-2017-5715, CVE-2017-5753