Linux kernel vulnerabilities A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS - Ubuntu 16.04 ESM - Ubuntu 14.04 ESM Summary Several security issues were fixed in the kernel. Software Description - linux - Linux kernel - linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems - linux-gke - Linux kernel for Google Container Engine (GKE) systems - linux-gkeop - Linux kernel for Google Container Engine (GKE) systems - linux-oem - Linux kernel for OEM systems Details Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host’s physical memory. (CVE-2021-3653) Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host’s physical memory. (CVE-2021-3656) Andy Nguyen discovered that the netfilter subsystem in the Linux kernel contained an out-of-bounds write in its setsockopt() implementation. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-22555) 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) Update instructions The problem can be corrected by updating your kernel livepatch to the following versions: Ubuntu 20.04 LTS gcp - 81.1 generic - 81.1 gke - 81.1 gkeop - 81.1 lowlatency - 81.1 Ubuntu 18.04 LTS generic - 81.1 gke - 81.1 gkeop - 81.1 lowlatency - 81.1 oem - 81.1 Ubuntu 16.04 ESM generic - 81.1 lowlatency - 81.1 Ubuntu 14.04 ESM generic - 81.1 lowlatency - 81.1 Support Information Kernels older than the levels listed below do not receive livepatch updates. If you are running a kernel version earlier than the one listed below, please upgrade your kernel as soon as possible. Ubuntu 20.04 LTS linux-aws - 5.4.0-1009 linux-azure - 5.4.0-1010 linux-gcp - 5.4.0-1009 linux-gke - 5.4.0-1033 linux-gkeop - 5.4.0-1009 linux-oem - 5.4.0-26 linux - 5.4.0-26 Ubuntu 18.04 LTS linux-aws - 4.15.0-1054 linux-gke-4.15 - 4.15.0-1076 linux-gke-5.4 - 5.4.0-1009 linux-gkeop-5.4 - 5.4.0-1007 linux-hwe-5.4 - 5.4.0-26 linux-oem - 4.15.0-1063 linux - 4.15.0-69 Ubuntu 16.04 ESM linux-aws - 4.4.0-1098 linux-azure - 4.15.0-1063 linux-azure - 4.15.0-1078 linux-hwe - 4.15.0-69 linux - 4.4.0-168 linux - 4.4.0-211 Ubuntu 14.04 ESM linux-lts-xenial - 4.4.0-168 References - CVE-2021-3653 - CVE-2021-3656 - CVE-2021-22555 - CVE-2021-33909 -- ubuntu-security-announce mailing list ubuntu-security-announce@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-security-announce