USN-4883-1: Linux kernel vulnerabilities

29 March 2021

Several security issues were fixed in the Linux kernel.



  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-aws-hwe - Linux kernel for Amazon Web Services (AWS-HWE) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-azure-4.15 - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gcp-4.15 - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-hwe - Linux hardware enablement (HWE) kernel
  • linux-kvm - Linux kernel for cloud environments
  • linux-oracle - Linux kernel for Oracle Cloud systems
  • linux-raspi2 - Linux kernel for Raspberry Pi (V8) systems
  • linux-snapdragon - Linux kernel for Qualcomm Snapdragon processors


Adam Nichols discovered that heap overflows existed in the iSCSI subsystem
in the Linux kernel. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2021-27365)

Adam Nichols discovered that the iSCSI subsystem in the Linux kernel did
not properly restrict access to iSCSI transport handles. A local attacker
could use this to cause a denial of service or expose sensitive information
(kernel pointer addresses). (CVE-2021-27363)

Adam Nichols discovered that an out-of-bounds read existed in the iSCSI
subsystem in the Linux kernel. A local attacker could use this to cause a
denial of service (system crash) or expose sensitive information (kernel
memory). (CVE-2021-27364)

Update instructions

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

Ubuntu 18.04
Ubuntu 16.04
Ubuntu 14.04

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.

Related notices

  • USN-4887-1: linux-image-5.4.0-1036-kvm, linux-image-5.4.0-1012-gkeop, linux-image-oem-20.04b, linux-image-gkeop-5.4, linux-image-gke, linux-image-oem, linux-image-5.10.0-1019-oem, linux-image-5.4.0-1041-aws, linux-image-5.8.0-1019-raspi, linux-hwe-5.8, linux-image-5.4.0-1040-gcp, linux-oem-5.6, linux-image-raspi-nolpae, linux-image-5.4.0-70-generic-lpae, linux-image-5.8.0-48-generic, linux-image-gke-5.3, linux-image-oem-osp1, linux-oracle-5.4, linux-azure-5.4, linux-image-lowlatency-hwe-20.04, linux-gkeop-5.4, linux-image-5.4.0-1039-gke, linux-image-generic-hwe-18.04, linux-image-generic-64k, linux-image-5.4.0-1032-raspi, linux-aws, linux-image-azure, linux-image-oracle, linux-image-5.8.0-1024-oracle, linux-azure, linux-image-oem-20.04, linux-image-raspi-hwe-18.04, linux-image-5.8.0-1027-aws, linux-image-5.3.0-72-lowlatency, linux-image-generic-lpae, linux-gcp-5.4, linux-image-gkeop, linux-image-5.8.0-1022-kvm, linux-raspi2-5.3, linux-image-generic, linux-hwe, linux-image-generic-lpae-hwe-20.04, linux-raspi, linux-gcp, linux-image-raspi2, linux-image-gkeop-5.3, linux-image-5.4.0-1041-oracle, linux-image-virtual, linux-image-5.8.0-48-generic-lpae, linux-hwe-5.4, linux-image-generic-lpae-hwe-18.04, linux-image-virtual-hwe-18.04, linux-image-5.4.0-70-generic, linux-image-aws, linux-image-5.3.0-1041-gke, linux-image-5.8.0-1026-gcp, linux-image-5.8.0-48-lowlatency, linux-image-5.4.0-70-lowlatency, linux-image-generic-hwe-20.04, linux-gkeop, linux-aws-5.4, linux-kvm, linux-image-snapdragon-hwe-18.04, linux-image-raspi, linux-image-raspi2-hwe-18.04, linux-gke-5.4, linux-image-5.6.0-1052-oem, linux-oem-5.10, linux-image-5.4.0-1043-azure, linux-image-kvm, linux-image-gke-5.4, linux-image-generic-64k-hwe-20.04, linux-image-5.8.0-1026-azure, linux-image-gcp, linux-image-lowlatency-hwe-18.04, linux-image-lowlatency, linux-oracle, linux-image-5.8.0-1019-raspi-nolpae, linux-gke-5.3, linux-image-5.3.0-1038-raspi2, linux-image-5.3.0-72-generic, linux-image-5.8.0-48-generic-64k, linux-image-virtual-hwe-20.04, linux-raspi-5.4, linux
  • USN-4901-1: linux-lts-trusty, linux-image-generic-lts-trusty, linux-image-3.13.0-185-generic
  • USN-4889-1: linux-image-generic-lpae-lts-xenial, linux-image-virtual-lts-xenial, linux-image-server, linux-lts-xenial, linux-image-4.4.0-206-generic-lpae, linux-image-lowlatency, linux-image-virtual, linux-image-3.13.0-185-generic-lpae, linux, linux-image-3.13.0-185-lowlatency, linux-image-generic-lpae, linux-image-4.4.0-206-lowlatency, linux-image-generic-lts-xenial, linux-image-lowlatency-lts-xenial, linux-image-generic, linux-image-4.4.0-206-generic, linux-image-3.13.0-185-generic, linux-image-generic-pae, linux-image-lowlatency-pae