--- title: 'USN-4977-1: Linux kernel vulnerabilities | Ubuntu security notices' description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/notices/USN-4977-1 --- 1. [Ubuntu Security Notices](https://ubuntu.com/security/notices) 2. USN-4977-1 --- # USN-4977-1: Linux kernel vulnerabilities Publication date 3 June 2021 Overview Several security issues were fixed in the Linux kernel. Releases [21.04](https://ubuntu.com/security/notices?release=hirsute) --- Open side navigation ## Packages * [linux](https://ubuntu.com/security/cves?package=linux) - Linux kernel * [linux-aws](https://ubuntu.com/security/cves?package=linux-aws) - Linux kernel for Amazon Web Services (AWS) systems * [linux-azure](https://ubuntu.com/security/cves?package=linux-azure) - Linux kernel for Microsoft Azure Cloud systems * [linux-gcp](https://ubuntu.com/security/cves?package=linux-gcp) - Linux kernel for Google Cloud Platform (GCP) systems * [linux-kvm](https://ubuntu.com/security/cves?package=linux-kvm) - Linux kernel for cloud environments * [linux-oracle](https://ubuntu.com/security/cves?package=linux-oracle) - Linux kernel for Oracle Cloud systems * [linux-raspi](https://ubuntu.com/security/cves?package=linux-raspi) - Linux kernel for Raspberry Pi (V8) systems ## Details Kiyin (尹亮) discovered that the NFC LLCP protocol implementation in the Linux kernel contained a reference counting error. A local attacker could use this to cause a denial of service (system crash). ([CVE-2020-25670](https://ubuntu.com/security/CVE-2020-25670)) Kiyin (尹亮) discovered that the NFC LLCP protocol implementation in the Linux kernel did not properly deallocate memory in certain error situations. A local attacker could use this to cause a denial of service (memory exhaustion). ([CVE-2020-25671](https://ubuntu.com/security/CVE-2020-25671), [CVE-2020-25672](https://ubuntu.com/security/CVE-2020-25672)) Kiyin (尹亮) discovered that the NFC LLCP protocol implementation in the Linux kernel did not properly handle error conditions in some situations, leading to an infinite loop. A local attacker could use this to cause a denial of service. ([CVE-2020-25673](https://ubuntu.com/security/CVE-2020-25673)) Piotr Krysiuk and Benedict Schlueter discovered that... --- Show more ## Update instructions After a standard system update you need to reboot your computer to make all the necessary changes. [Learn more about how to get the fixes.](https://ubuntu.com/security/cves/about#security) 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. The problem can be corrected by updating your system to the following package versions: | Ubuntu Release | Package Version | | --- | --- | | 21.04 hirsute | [linux-image-5.11.0-1006-azure](https://launchpad.net/ubuntu/+source/linux-signed-azure) –  [5.11.0-1006.6](https://launchpad.net/ubuntu/+source/linux-signed-azure/5.11.0-1006.6) | | | | [linux-image-5.11.0-1007-oracle](https://launchpad.net/ubuntu/+source/linux-signed-oracle) –  [5.11.0-1007.7](https://launchpad.net/ubuntu/+source/linux-signed-oracle/5.11.0-1007.7) | | | | [linux-image-5.11.0-1008-aws](https://launchpad.net/ubuntu/+source/linux-aws) –  [5.11.0-1008.8](https://launchpad.net/ubuntu/+source/linux-aws/5.11.0-1008.8) | | | | [linux-image-5.11.0-1008-gcp](https://launchpad.net/ubuntu/+source/linux-signed-gcp) –  [5.11.0-1008.9](https://launchpad.net/ubuntu/+source/linux-signed-gcp/5.11.0-1008.9) | | | | [linux-image-5.11.0-1008-kvm](https://launchpad.net/ubuntu/+source/linux-signed-kvm) –  [5.11.0-1008.8](https://launchpad.net/ubuntu/+source/linux-signed-kvm/5.11.0-1008.8) | | | | [linux-image-5.11.0-1009-raspi](https://launchpad.net/ubuntu/+source/linux-raspi) –  [5.11.0-1009.10](https://launchpad.net/ubuntu/+source/linux-raspi/5.11.0-1009.10) | | | | [linux-image-5.11.0-1009-raspi-nolpae](https://launchpad.net/ubuntu/+source/linux-raspi) –  [5.11.0-1009.10](https://launchpad.net/ubuntu/+source/linux-raspi/5.11.0-1009.10) | | | | [linux-image-5.11.0-18-generic](https://launchpad.net/ubuntu/+source/linux-signed) –  [5.11.0-18.19](https://launchpad.net/ubuntu/+source/linux-signed/5.11.0-18.19) | | | | [linux-image-5.11.0-18-generic-64k](https://launchpad.net/ubuntu/+source/linux-signed) –  [5.11.0-18.19](https://launchpad.net/ubuntu/+source/linux-signed/5.11.0-18.19) | | | | [linux-image-5.11.0-18-generic-lpae](https://launchpad.net/ubuntu/+source/linux) –  [5.11.0-18.19](https://launchpad.net/ubuntu/+source/linux/5.11.0-18.19) | | | | [linux-image-5.11.0-18-lowlatency](https://launchpad.net/ubuntu/+source/linux-signed) –  [5.11.0-18.19](https://launchpad.net/ubuntu/+source/linux-signed/5.11.0-18.19) | | | | [linux-image-aws](https://launchpad.net/ubuntu/+source/linux-meta-aws) –  [5.11.0.1008.8](https://launchpad.net/ubuntu/+source/linux-meta-aws/5.11.0.1008.8) | | | | [linux-image-azure](https://launchpad.net/ubuntu/+source/linux-meta-azure) –  [5.11.0.1006.6](https://launchpad.net/ubuntu/+source/linux-meta-azure/5.11.0.1006.6) | | | | [linux-image-gcp](https://launchpad.net/ubuntu/+source/linux-meta-gcp) –  [5.11.0.1008.8](https://launchpad.net/ubuntu/+source/linux-meta-gcp/5.11.0.1008.8) | | | | [linux-image-generic](https://launchpad.net/ubuntu/+source/linux-meta) –  [5.11.0.18.19](https://launchpad.net/ubuntu/+source/linux-meta/5.11.0.18.19) | | | | [linux-image-generic-64k](https://launchpad.net/ubuntu/+source/linux-meta) –  [5.11.0.18.19](https://launchpad.net/ubuntu/+source/linux-meta/5.11.0.18.19) | | | | [linux-image-generic-lpae](https://launchpad.net/ubuntu/+source/linux-meta) –  [5.11.0.18.19](https://launchpad.net/ubuntu/+source/linux-meta/5.11.0.18.19) | | | | [linux-image-gke](https://launchpad.net/ubuntu/+source/linux-meta-gcp) –  [5.11.0.1008.8](https://launchpad.net/ubuntu/+source/linux-meta-gcp/5.11.0.1008.8) | | | | [linux-image-kvm](https://launchpad.net/ubuntu/+source/linux-meta-kvm) –  [5.11.0.1008.8](https://launchpad.net/ubuntu/+source/linux-meta-kvm/5.11.0.1008.8) | | | | [linux-image-lowlatency](https://launchpad.net/ubuntu/+source/linux-meta) –  [5.11.0.18.19](https://launchpad.net/ubuntu/+source/linux-meta/5.11.0.18.19) | | | | [linux-image-oracle](https://launchpad.net/ubuntu/+source/linux-meta-oracle) –  [5.11.0.1007.7](https://launchpad.net/ubuntu/+source/linux-meta-oracle/5.11.0.1007.7) | | | | [linux-image-raspi](https://launchpad.net/ubuntu/+source/linux-meta-raspi) –  [5.11.0.1009.7](https://launchpad.net/ubuntu/+source/linux-meta-raspi/5.11.0.1009.7) | | | | [linux-image-raspi-nolpae](https://launchpad.net/ubuntu/+source/linux-meta-raspi) –  [5.11.0.1009.7](https://launchpad.net/ubuntu/+source/linux-meta-raspi/5.11.0.1009.7) | | | | [linux-image-virtual](https://launchpad.net/ubuntu/+source/linux-meta) –  [5.11.0.18.19](https://launchpad.net/ubuntu/+source/linux-meta/5.11.0.18.19) | | | --- ### Reduce your security exposure Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines. [Get Ubuntu Pro](https://ubuntu.com/pro) ## References * [CVE-2021-3501](https://ubuntu.com/security/CVE-2021-3501) * [CVE-2021-29155](https://ubuntu.com/security/CVE-2021-29155) * [CVE-2020-25673](https://ubuntu.com/security/CVE-2020-25673) * [CVE-2020-25672](https://ubuntu.com/security/CVE-2020-25672) * [CVE-2020-25671](https://ubuntu.com/security/CVE-2020-25671) * [CVE-2020-25670](https://ubuntu.com/security/CVE-2020-25670) ## Related notices * [USN-5343-1](https://ubuntu.com/security/notices/USN-5343-1) * [USN-4999-1](https://ubuntu.com/security/notices/USN-4999-1) * [USN-4983-1](https://ubuntu.com/security/notices/USN-4983-1) * [USN-4982-1](https://ubuntu.com/security/notices/USN-4982-1) * [USN-4979-1](https://ubuntu.com/security/notices/USN-4979-1) * [USN-4948-1](https://ubuntu.com/security/notices/USN-4948-1) --- Have additional questions? 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