Security Advisory Desk
unratedQCS priority 70/100Ubuntu

USN-8633-1: Linux kernel vulnerabilities

Multiple security flaws were found in the Linux kernel used by Ubuntu. One notable bug allows an attacker physically near your device to inject malicious WiFi packets because of a problem in handling certain WiFi frames in mesh networks. Other issues affect various parts of the kernel and could let attackers compromise your system.

Published 12/8/2026, 7:54:20 pmVerified 13/8/2026, 2:40:27 amRevision 1
Ubuntu unrated network security advisory visual

In plain language

What this advisory means

Multiple security flaws were found in the Linux kernel used by Ubuntu. One notable bug allows an attacker physically near your device to inject malicious WiFi packets because of a problem in handling certain WiFi frames in mesh networks. Other issues affect various parts of the kernel and could let attackers compromise your system.

Technical explanation

How the issue affects the environment

Researchers Siebe Devroe, Héloïse Gollier, and Mathy Vanhoef discovered that the Linux kernel's WiFi implementation improperly handled aggregated frames in mesh networks due to an incorrect fix for CVE-2020-24588. This flaw (CVE-2025-27558) allows a physically proximate attacker to inject packets. Additionally, various vulnerabilities were identified across several kernel subsystems including the x86 architecture, cryptographic API, GPU drivers, network drivers, file systems (Ext4), IPv4 and IPv6 networking stacks, TCP, SCTP, multipath TCP, and others. Exploiting these could potentially compromise system integrity or confidentiality. Kernel updates addressing these flaws have been released.

Operational impact

Why teams should care

If exploited, these vulnerabilities could allow attackers, particularly those physically nearby, to inject malicious packets or otherwise compromise the confidentiality, integrity, and availability of affected Ubuntu systems. This may lead to unauthorized access, disruption of services, or data exposure, impacting business operations and security.

Immediate action

Users should update their Ubuntu Linux kernel packages to the versions released as part of this security update, which address the noted vulnerabilities. After updating, a system reboot is required to apply all changes. Note that the kernel updates include unavoidable ABI changes, so any third-party kernel modules must 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

  • Discovery of WiFi frame handling bug due to incorrect fix for CVE-2020-24588 by Devroe, Gollier, and Vanhoef.
  • Potential for physically proximate attackers to inject packets (CVE-2025-27558).
  • Multiple other vulnerabilities identified across kernel subsystems including networking, filesystems, drivers, and cryptographic API.
  • Advisory mentions attackers could possibly compromise systems using these flaws.
  • Official recommendation to update to fixed Linux kernel versions and reboot.
  • Noted ABI change requiring recompilation of third-party kernel modules after update.

Authoritative reference

Ubuntu Security Notices

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

Open source
USN-8633-1: Linux kernel vulnerabilities | Advisory | QCS