USN-8389-1

Description

linux, linux-aws, linux-aws-fips, linux-azure, linux-azure-5.4, linux-azure-fips, linux-bluefield, linux-fips, linux-gcp, linux-gcp-5.4, linux-gcp-fips, linux-iot, linux-kvm, linux-oracle, linux-oracle-5.4, linux-xilinx-zynqmp vulnerabilities It was discovered that the Linux kernel did not properly handle shared page fragments during socket buffer operations, collectively known as Dirty Frag. A logic flaw existed in the XFRM ESP-in-TCP subsystem and in the RxRPC networking subsystem when processing paged fragments. A local attacker could use this to escalate privileges, or possibly escape a container. (CVE-2026-43284, CVE-2026-43500) Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - RDS protocol; (CVE-2026-43494)

Affected Systems

• ubuntu•linux

  < 5.4.0-231.251

• ubuntu•linux-aws

  < 5.4.0-1160.170

• ubuntu•linux-aws-fips

  < 5.4.0-1160.170+fips1

• ubuntu•linux-azure

  < 5.4.0-1164.170

• ubuntu•linux-azure-5.4

  < 5.4.0-1164.170~18.04.1

• ubuntu•linux-azure-fips

  < 5.4.0-1164.170+fips1

• ubuntu•linux-bluefield

  < 5.4.0-1119.126

• ubuntu•linux-fips

  < 5.4.0-1134.144

• ubuntu•linux-gcp

  < 5.4.0-1163.172

• ubuntu•linux-gcp-5.4

  < 5.4.0-1163.172~18.04.1

• ubuntu•linux-gcp-fips

  < 5.4.0-1163.172+fips1

• ubuntu•linux-iot

  < 5.4.0-1064.67

• ubuntu•linux-kvm

  < 5.4.0-1147.156

• ubuntu•linux-oracle

  < 5.4.0-1158.168

• ubuntu•linux-oracle-5.4

  < 5.4.0-1158.168~18.04.1

• ubuntu•linux-xilinx-zynqmp

  < 5.4.0-1078.82

References (4)

• https://ubuntu.com/security/notices/USN-8389-1
• https://ubuntu.com/security/CVE-2026-43284
• https://ubuntu.com/security/CVE-2026-43494
• https://ubuntu.com/security/CVE-2026-43500