Security Advisory Desk
unratedQCS priority 70/100Ubuntu

USN-8636-1: Linux kernel vulnerabilities

Multiple security vulnerabilities were found in the Linux kernel used by Ubuntu. These weaknesses could let attackers take control of affected systems. The issues affect a wide range of kernel components and drivers, including network and file system elements. Ubuntu has released updates to fix these problems and users should apply them promptly and reboot to protect their systems.

Published 12/8/2026, 8:06:15 pmVerified 13/8/2026, 12:04:28 amRevision 1
Ubuntu unrated network security advisory visual

In plain language

What this advisory means

Multiple security vulnerabilities were found in the Linux kernel used by Ubuntu. These weaknesses could let attackers take control of affected systems. The issues affect a wide range of kernel components and drivers, including network and file system elements. Ubuntu has released updates to fix these problems and users should apply them promptly and reboot to protect their systems.

Technical explanation

How the issue affects the environment

A series of vulnerabilities were identified across diverse subsystems within the Linux kernel on Ubuntu, including but not limited to x86 architecture, InfiniBand, media and network drivers (including Mellanox and Texas Instruments), NVME storage, file system infrastructure, SMB network file system, IPv4 and IPv6 networking stacks, TCP/IP protocols, locking primitives, memory management, Multipath TCP, Netfilter, RxRPC session sockets, SCTP protocol, and SMC sockets. These flaws could be exploited by an attacker to compromise system integrity or confidentiality. The update involves kernel version 6.17 and requires recompilation of third-party kernel modules due to an ABI change. A system reboot is mandatory after installation to apply changes.

Operational impact

Why teams should care

If unpatched, these vulnerabilities could allow attackers to compromise Ubuntu systems, potentially accessing sensitive data, disrupting services, or gaining unauthorized control. This can lead to operational downtime, data breaches, and damage to organizational reputation. Timely updates are critical to mitigate risk and maintain system security posture.

Immediate action

Users should update their Ubuntu systems to the specified kernel versions that include security fixes. After installing updates, a system reboot is required to apply all changes. Note that kernel updates introduce an ABI change; therefore, any third-party kernel modules must be recompiled and reinstalled to maintain compatibility.

Affected and fixed releases

Affected versionsLinux kernel versions prior to 6.17.0-42.42 and related kernel versions for Ubuntu 24.04 LTS and its flavors
Fixed versionsLinux kernel 6.17.0-42.42 and later, including linux-image-6.17.0-1019.22, linux-image-6.17.0-1022.22, linux-image-6.17.0-1032.32, and related kernel packages

Temporary risk reduction

The advisory does not specify any workaround. Applying the full kernel update and rebooting is necessary to mitigate the vulnerabilities.

Evidence and validation checklist

  • Official Ubuntu Security Notice USN-8636-1
  • Ubuntu kernel package version updates
  • List of affected kernel subsystems and drivers
  • Requirement to reboot after update
  • ABI change requiring recompilation of third-party kernel modules

Authoritative reference

Ubuntu Security Notices

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

Open source