==========================================================================
Ubuntu Security Notice USN-7853-1
October 30, 2025

linux, linux-aws, linux-aws-hwe, linux-gcp, linux-gcp-4.15, linux-hwe,
linux-oracle vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-gcp-4.15: Linux kernel for Google Cloud Platform (GCP) systems
- linux-oracle: Linux kernel for Oracle Cloud systems
- linux-aws-hwe: Linux kernel for Amazon Web Services (AWS-HWE) systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-hwe: Linux hardware enablement (HWE) kernel

Details:

Jean-Claude Graf, Sandro Rüegge, Ali Hajiabadi, and Kaveh Razavi discovered
that the Linux kernel contained insufficient branch predictor isolation
between a guest and a userspace hypervisor for certain processors. This
flaw is known as VMSCAPE. An attacker in a guest VM could possibly use this
to expose sensitive information from the host OS. (CVE-2025-40300)

Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
   - DMA engine subsystem;
   - GPU drivers;
   - HSI subsystem;
   - Ethernet team driver;
   - Ext4 file system;
   - Timer subsystem;
   - DCCP (Datagram Congestion Control Protocol);
   - IPv6 networking;
   - NET/ROM layer;
   - SCTP protocol;
   - USB sound devices;
(CVE-2023-52574, CVE-2023-52650, CVE-2024-41006, CVE-2024-50006,
CVE-2024-50299, CVE-2024-53124, CVE-2024-53150, CVE-2024-56767,
CVE-2025-37838, CVE-2025-38352)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 18.04 LTS
   linux-image-4.15.0-1148-oracle  4.15.0-1148.159
                                   Available with Ubuntu Pro
   linux-image-4.15.0-1179-gcp     4.15.0-1179.196
                                   Available with Ubuntu Pro
   linux-image-4.15.0-1186-aws     4.15.0-1186.199
                                   Available with Ubuntu Pro
   linux-image-4.15.0-243-generic  4.15.0-243.255
                                   Available with Ubuntu Pro
   linux-image-4.15.0-243-lowlatency  4.15.0-243.255
                                   Available with Ubuntu Pro
   linux-image-aws-4.15            4.15.0.1186.184
                                   Available with Ubuntu Pro
   linux-image-aws-lts-18.04       4.15.0.1186.184
                                   Available with Ubuntu Pro
   linux-image-gcp-4.15            4.15.0.1179.192
                                   Available with Ubuntu Pro
   linux-image-gcp-lts-18.04       4.15.0.1179.192
                                   Available with Ubuntu Pro
   linux-image-generic             4.15.0.243.227
                                   Available with Ubuntu Pro
   linux-image-lowlatency          4.15.0.243.227
                                   Available with Ubuntu Pro
   linux-image-oracle-4.15         4.15.0.1148.153
                                   Available with Ubuntu Pro
   linux-image-oracle-lts-18.04    4.15.0.1148.153
                                   Available with Ubuntu Pro
   linux-image-virtual             4.15.0.243.227
                                   Available with Ubuntu Pro

Ubuntu 16.04 LTS
   linux-image-4.15.0-1179-gcp     4.15.0-1179.196~16.04.1
                                   Available with Ubuntu Pro
   linux-image-4.15.0-1186-aws     4.15.0-1186.199~16.04.1
                                   Available with Ubuntu Pro
   linux-image-4.15.0-243-generic  4.15.0-243.255~16.04.1
                                   Available with Ubuntu Pro
   linux-image-4.15.0-243-lowlatency  4.15.0-243.255~16.04.1
                                   Available with Ubuntu Pro
   linux-image-aws-hwe             4.15.0.1186.199~16.04.1
                                   Available with Ubuntu Pro
   linux-image-gcp                 4.15.0.1179.196~16.04.1
                                   Available with Ubuntu Pro
   linux-image-generic-hwe-16.04   4.15.0.243.255~16.04.1
                                   Available with Ubuntu Pro
   linux-image-gke                 4.15.0.1179.196~16.04.1
                                   Available with Ubuntu Pro
   linux-image-lowlatency-hwe-16.04  4.15.0.243.255~16.04.1
                                   Available with Ubuntu Pro
   linux-image-oem                 4.15.0.243.255~16.04.1
                                   Available with Ubuntu Pro
   linux-image-virtual-hwe-16.04   4.15.0.243.255~16.04.1
                                   Available with Ubuntu Pro

After a standard system update you need to reboot your computer to make
all the necessary changes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have
been given a new version number, which requires you to recompile and
reinstall all third party kernel modules you might have installed.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

References:
   https://ubuntu.com/security/notices/USN-7853-1
   CVE-2023-52574, CVE-2023-52650, CVE-2024-41006, CVE-2024-50006,
   CVE-2024-50299, CVE-2024-53124, CVE-2024-53150, CVE-2024-56767,
   CVE-2025-37838, CVE-2025-38352, CVE-2025-40300