Security Advisory Desk
unratedQCS priority 70/100Ubuntu

USN-8630-1: Linux kernel vulnerabilities

The Linux kernel in Ubuntu contains multiple security vulnerabilities affecting various parts of the system. An attacker could exploit these weaknesses to take control or compromise the system. Ubuntu has released updates to fix these vulnerabilities, and users should update and reboot their systems to protect themselves.

Published 12/8/2026, 7:43:13 pmVerified 13/8/2026, 5:58:55 amRevision 1
Ubuntu unrated network security advisory visual

In plain language

What this advisory means

The Linux kernel in Ubuntu contains multiple security vulnerabilities affecting various parts of the system. An attacker could exploit these weaknesses to take control or compromise the system. Ubuntu has released updates to fix these vulnerabilities, and users should update and reboot their systems to protect themselves.

Technical explanation

How the issue affects the environment

Multiple security issues were identified in the Linux kernel spanning several subsystems including x86 architecture, InfiniBand and Mellanox network drivers, general network drivers, file system infrastructure, IPv4 and IPv6 networking stacks, network traffic control, TCP, B.A.T.M.A.N. meshing protocol, Multipath TCP, Netfilter, RxRPC session sockets, SCTP, and SMC sockets. Exploiting these flaws could permit attackers to compromise kernel integrity or gain unauthorized access. Ubuntu has addressed these flaws through a kernel update that also includes an unavoidable ABI (Application Binary Interface) change, necessitating recompilation of third-party kernel modules.

Operational impact

Why teams should care

Organizations running vulnerable Ubuntu Linux kernels risk potential system compromises that could lead to unauthorized data access, service disruption, or broader network infiltration. Failure to apply these updates may expose critical infrastructure to exploitation by attackers.

Immediate action

System administrators should apply the security update packages provided by Ubuntu for their specific kernel versions. After installation, a full system reboot is required to complete the updates. Note that due to an ABI change, any installed third-party kernel modules need to be recompiled and reinstalled to maintain compatibility.

Affected and fixed releases

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

Temporary risk reduction

No separate workaround was supplied in the source feed. Use the official vendor advisory before changing production controls.

Evidence and validation checklist

  • Multiple security issues discovered in Linux kernel subsystems
  • Affected subsystems include various network drivers and protocols, file systems, and architecture components
  • Update requires system reboot
  • An ABI change requires recompilation of third-party kernel modules
  • Security update packages released by Ubuntu for various kernel flavors and platforms
  • No specific CVSS scores or severity ratings provided in the advisory

Authoritative reference

Ubuntu Security Notices

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

Open source