Security Advisory Desk
unratedQCS priority 70/100Ubuntu

USN-8634-1: Linux kernel vulnerabilities

Multiple security weaknesses were found in the Linux kernel, which is the core of the Ubuntu operating system. Attackers could use these vulnerabilities to take control of or harm affected systems. This update fixes problems in many parts of the kernel, including hardware support, network communication, file systems, and encryption. Users should update their systems and reboot to protect themselves.

Published 12/8/2026, 7:54:57 pmVerified 13/8/2026, 12:04:40 amRevision 1
Ubuntu unrated network security advisory visual

In plain language

What this advisory means

Multiple security weaknesses were found in the Linux kernel, which is the core of the Ubuntu operating system. Attackers could use these vulnerabilities to take control of or harm affected systems. This update fixes problems in many parts of the kernel, including hardware support, network communication, file systems, and encryption. Users should update their systems and reboot to protect themselves.

Technical explanation

How the issue affects the environment

The Linux kernel contained several vulnerabilities affecting diverse subsystems such as the x86 CPU architecture, Cryptographic API, InfiniBand and media drivers, various network drivers including STMicroelectronics, network protocols (IPv4, IPv6, TCP, SCTP, Multipath TCP, Netfilter, SMC sockets), file systems like Ext4, locking primitives, the B.A.T.M.A.N. meshing protocol, and the Ceph Core library. These flaws could potentially allow attackers to compromise system integrity or gain unauthorized access. The update introduces patched kernel versions that resolve these issues, necessitating a system reboot and recompilation of external kernel modules due to ABI changes.

Operational impact

Why teams should care

If unaddressed, these vulnerabilities could allow attackers to compromise systems running Ubuntu, leading to data breaches, service disruption, and loss of user trust. Organizations relying on affected Ubuntu systems must apply updates promptly to maintain security and compliance.

Immediate action

Users should update their Ubuntu systems using the standard update process to install the fixed kernel versions provided. A system reboot is required after updating to activate these patches. Because of an unavoidable Application Binary Interface (ABI) change, users must recompile and reinstall any third-party kernel modules to ensure compatibility with the new kernel.

Affected and fixed releases

Affected versionsConfirm in the official vendor advisory
Fixed versionsConfirm in the official vendor advisory

Temporary risk reduction

The advisory does not specify any workaround. Applying the update and rebooting the system is required to address the vulnerabilities effectively.

Evidence and validation checklist

  • Multiple security issues found in the Linux kernel affecting various subsystems.
  • Potential attacker use to compromise system integrity or security.
  • Update fixes multiple subsystems including network protocols, drivers, and filesystems.
  • Update requires reboot and recompilation of third-party kernel modules due to ABI changes.
  • No explicit information on exploitation or workaround provided.

Authoritative reference

Ubuntu Security Notices

QCS detected and normalized this record from the official source. Vendor guidance remains authoritative.

Open source