USN-4017-2: Linux kernel vulnerabilities

17 June 2019

linux, linux-aws, linux-azure, linux-lts-trusty, linux-lts-xenial vulnerabilities

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

  • Ubuntu 14.04 ESM
  • Ubuntu 12.04 ESM


The system could be made to crash if it received specially crafted network traffic.

Software Description

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty
  • linux-lts-trusty - Linux hardware enablement kernel from Trusty for Precise ESM


USN-4017-1 fixed vulnerabilities in the Linux kernel for Ubuntu. This update provides the corresponding updates for the Linux kernel for Ubuntu 16.04 ESM and Ubuntu 14.04 ESM.

Jonathan Looney discovered that the TCP retransmission queue implementation in the Linux kernel could be fragmented when handling certain TCP Selective Acknowledgment (SACK) sequences. A remote attacker could use this to cause a denial of service. (CVE-2019-11478)

Jonathan Looney discovered that an integer overflow existed in the Linux kernel when handling TCP Selective Acknowledgments (SACKs). A remote attacker could use this to cause a denial of service (system crash). (CVE-2019-11477)

Update instructions

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

Ubuntu 14.04 ESM
linux-image-3.13.0-171-generic - 3.13.0-171.222
linux-image-3.13.0-171-generic-lpae - 3.13.0-171.222
linux-image-3.13.0-171-lowlatency - 3.13.0-171.222
linux-image-4.15.0-1047-azure - 4.15.0-1047.51~14.04.1
linux-image-4.4.0-1046-aws - 4.4.0-1046.50
linux-image-4.4.0-151-generic - 4.4.0-151.178~14.04.1
linux-image-4.4.0-151-generic-lpae - 4.4.0-151.178~14.04.1
linux-image-4.4.0-151-lowlatency - 4.4.0-151.178~14.04.1
linux-image-aws -
linux-image-azure -
linux-image-generic -
linux-image-generic-lpae -
linux-image-generic-lpae-lts-xenial -
linux-image-generic-lts-xenial -
linux-image-lowlatency-lts-xenial -
Ubuntu 12.04 ESM
linux-image-3.13.0-171-generic - 3.13.0-171.222~12.04.1
linux-image-3.13.0-171-generic-lpae - 3.13.0-171.222~12.04.1
linux-image-3.13.0-171-lowlatency - 3.13.0-171.222~12.04.1
linux-image-3.2.0-141-generic - 3.2.0-141.188
linux-image-generic -
linux-image-generic-lpae-lts-trusty -
linux-image-generic-lts-trusty -

To update your system, please follow these instructions:

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.