USN-4916-1

Description

linux, linux-aws, linux-aws-hwe, linux-azure, linux-azure-4.15, linux-dell300x, linux-gcp, linux-gcp-4.15, linux-hwe, linux-kvm, linux-lts-xenial, linux-oracle, linux-raspi2, linux-snapdragon vulnerabilities It was discovered that the overlayfs implementation in the Linux kernel did not properly validate the application of file system capabilities with respect to user namespaces. A local attacker could use this to gain elevated privileges. (CVE-2021-3493) Piotr Krysiuk discovered that the BPF JIT compiler for x86 in the Linux kernel did not properly validate computation of branch displacements in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-29154)

Affected Systems

• ubuntu•linux

  < 4.4.0-209.241 | < 4.15.0-142.146

• ubuntu•linux-aws

  < 4.4.0-1091.95 | < 4.4.0-1127.141 | < 4.15.0-1099.106

• ubuntu•linux-aws-hwe

  < 4.15.0-1099.106~16.04.1

• ubuntu•linux-azure

  < 4.15.0-1113.126~14.04.1 | < 4.15.0-1113.126~16.04.1

• ubuntu•linux-azure-4.15

  < 4.15.0-1113.126

• ubuntu•linux-dell300x

  < 4.15.0-1017.21

• ubuntu•linux-gcp

  < 4.15.0-1098.111~16.04.1

• ubuntu•linux-gcp-4.15

  < 4.15.0-1098.111

• ubuntu•linux-hwe

  < 4.15.0-142.146~16.04.1

• ubuntu•linux-kvm

  < 4.4.0-1092.101 | < 4.15.0-1090.92

• ubuntu•linux-lts-xenial

  < 4.4.0-209.241~14.04.1

• ubuntu•linux-oracle

  < 4.15.0-1070.78~16.04.1 | < 4.15.0-1070.78

• ubuntu•linux-raspi2

  < 4.4.0-1151.162 | < 4.15.0-1084.89

• ubuntu•linux-snapdragon

  < 4.4.0-1155.165 | < 4.15.0-1101.110

References (3)

• https://ubuntu.com/security/notices/USN-4916-1
• https://ubuntu.com/security/CVE-2021-3493
• https://ubuntu.com/security/CVE-2021-29154