1. Ubuntu Security Notices
  2. USN-8635-1

USN-8635-1: Linux kernel (Azure) vulnerabilities

Publication date

12 August 2026

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

  • linux-azure - Linux kernel for Microsoft Azure Cloud systems

Details

Siebe Devroe, Héloïse Gollier, and Mathy Vanhoef discovered that the WiFi
implementation in the Linux kernel did not properly handle aggregated
frames in mesh networks, due to an incorrect fix for CVE-2020-24588. A
physically proximate attacker could use this issue to inject packets.
(CVE-2025-27558)

It was discovered that a logic flaw existed in the XFRM ESP-in-TCP
subsystem in the Linux kernel when handling socket buffer fragments. This
flaw is known as Fragnesia. A local attacker could use this to escalate
privileges, or possibly escape a container. (CVE-2026-43503)

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:

  • x86 architecture;
  • Cryptographic...

Siebe Devroe, Héloïse Gollier, and Mathy Vanhoef discovered that the WiFi
implementation in the Linux kernel did not properly handle aggregated
frames in mesh networks, due to an incorrect fix for CVE-2020-24588. A
physically proximate attacker could use this issue to inject packets.
(CVE-2025-27558)

It was discovered that a logic flaw existed in the XFRM ESP-in-TCP
subsystem in the Linux kernel when handling socket buffer fragments. This
flaw is known as Fragnesia. A local attacker could use this to escalate
privileges, or possibly escape a container. (CVE-2026-43503)

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:

  • x86 architecture;
  • Cryptographic API;
  • GPU drivers;
  • InfiniBand drivers;
  • Media drivers;
  • NVIDIA Tegra memory controller driver;
  • Network drivers;
  • STMicroelectronics network drivers;
  • NVME drivers;
  • SCSI subsystem;
  • Thermal drivers;
  • USB over IP driver;
  • Ext4 file system;
  • Network file system (NFS) server daemon;
  • SMB network file system;
  • IPv4 networking;
  • Network traffic control;
  • TCP network protocol;
  • Tracing infrastructure;
  • Locking primitives;
  • B.A.T.M.A.N. meshing protocol;
  • Ethernet bridge;
  • Ceph Core library;
  • DCCP (Datagram Congestion Control Protocol);
  • IPv6 networking;
  • Multipath TCP;
  • Netfilter;
  • RxRPC session sockets;
  • SCTP protocol;
  • SMC sockets;
  • X.25 network layer

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.

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
14.04 LTS trusty linux-image-4.15.0-1205-azure –  4.15.0-1205.220~14.04.1  
linux-image-azure –  4.15.0.1205.220~14.04.1  

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References

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