Security Advisory Desk
unratedQCS priority 76/100Ubuntu

USN-8620-4: Linux kernel (Intel IoTG) vulnerabilities

Several security vulnerabilities were found in the Linux kernel used by Ubuntu, including issues that could allow attackers to access sensitive information or escalate their privileges. One notable vulnerability in the NTFS file system could let attackers expose kernel memory by using a specially crafted malicious NTFS image. Other vulnerabilities involve certain AMD processors, where attackers with local access might leak sensitive data or gain higher-level access. This update addresses various flaws across many Linux kernel subsystems to enhance system security.

Published 31/7/2026, 3:00:56 pmVerified 31/7/2026, 7:25:08 pmRevision 1
Ubuntu unrated network security advisory visual

In plain language

What this advisory means

Several security vulnerabilities were found in the Linux kernel used by Ubuntu, including issues that could allow attackers to access sensitive information or escalate their privileges. One notable vulnerability in the NTFS file system could let attackers expose kernel memory by using a specially crafted malicious NTFS image. Other vulnerabilities involve certain AMD processors, where attackers with local access might leak sensitive data or gain higher-level access. This update addresses various flaws across many Linux kernel subsystems to enhance system security.

Technical explanation

How the issue affects the environment

Maxim Suhanov identified that the NTFS file system implementation in the Linux kernel failed to properly validate file name length in certain cases, resulting in an out-of-bounds read (CVE-2023-45896). This can be exploited by crafting a malicious NTFS image, which, when mounted and manipulated, can leak kernel memory content. Additionally, some AMD processors do not correctly clear data in the floating point divider unit during speculative execution (CVE-2025-54505), potentially allowing local attackers to expose sensitive information. Furthermore, AMD Zen 2 processors have inadequate isolation of shared resources in the operation cache (CVE-2025-54518), possibly permitting local privilege escalation by corrupting instructions executed at higher privilege levels. This security update resolves multiple vulnerabilities across numerous kernel subsystems, including ARM, MIPS, PowerPC, x86 architectures and drivers related to networking, file systems, audio, USB, and several others, preventing potential system compromise.

Operational impact

Why teams should care

If exploited, these Linux kernel vulnerabilities could lead to exposure of sensitive kernel memory contents and local privilege escalation, potentially compromising the security and integrity of affected Ubuntu systems. Organizations running vulnerable kernel versions may face risks of data leakage or unauthorized system control, leading to operational disruptions or breaches.

Immediate action

Users should update their Linux kernel packages to the fixed versions provided by Ubuntu (e.g., linux-image-5.15.0-1107-intel-iotg version 5.15.0-1107.113) and reboot their systems to apply the security corrections. Additionally, due to an ABI change in the kernel update, third-party kernel modules need to be recompiled and reinstalled to function correctly.

Affected and fixed releases

Affected versionsConfirm in the official vendor advisory
Fixed versions5.15.0-1107.113, 5.15.0.1107.106

Temporary risk reduction

The official advisory does not specify any workarounds. The recommended action is to apply the provided kernel updates and reboot the system.

Evidence and validation checklist

  • Advisory from Ubuntu Security Notices USN-8620-4 dated 31 July 2026
  • Description of CVE-2023-45896 affecting NTFS file system and enabling kernel memory exposure
  • Details of speculative execution data clearing issue in AMD processors (CVE-2025-54505)
  • Details of shared resource isolation flaw in AMD Zen 2 processors (CVE-2025-54518)
  • Listing of multiple affected kernel subsystems and architectures
  • Update instructions including new kernel package versions and required module recompilation

Authoritative reference

Ubuntu Security Notices

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

Open source
USN-8620-4: Linux kernel (Intel IoTG) | Advisory | QCS