1. Ubuntu Security Notices
  2. USN-7910-1

USN-7910-1: Linux kernel (Azure FIPS) vulnerabilities

Publication date

4 December 2025

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

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:

  • ARM32 architecture;
  • ARM64 architecture;
  • MIPS architecture;
  • PowerPC architecture;
  • RISC-V architecture;
  • S390 architecture;
  • x86 architecture;
  • Block layer subsystem;
  • ACPI drivers;
  • ATM drivers;
  • DRBD Distributed Replicated Block Device drivers;
  • Bus devices;
  • Clock...

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:

  • ARM32 architecture;
  • ARM64 architecture;
  • MIPS architecture;
  • PowerPC architecture;
  • RISC-V architecture;
  • S390 architecture;
  • x86 architecture;
  • Block layer subsystem;
  • ACPI drivers;
  • ATM drivers;
  • DRBD Distributed Replicated Block Device drivers;
  • Bus devices;
  • Clock framework and drivers;
  • Data acquisition framework and drivers;
  • Hardware crypto device drivers;
  • Device frequency scaling framework;
  • Buffer Sharing and Synchronization framework;
  • DMA engine subsystem;
  • ARM SCMI message protocol;
  • GPU drivers;
  • HID subsystem;
  • Hardware monitoring drivers;
  • I2C subsystem;
  • I3C subsystem;
  • IIO subsystem;
  • InfiniBand drivers;
  • Input Device core drivers;
  • IOMMU subsystem;
  • Media drivers;
  • Network drivers;
  • Mellanox network drivers;
  • PCI subsystem;
  • PCCARD (PCMCIA/CardBus) bus subsystem;
  • PHY drivers;
  • Power supply drivers;
  • Voltage and Current Regulator drivers;
  • SCSI subsystem;
  • ASPEED SoC drivers;
  • QCOM SoC drivers;
  • small TFT LCD display modules;
  • Trusted Execution Environment drivers;
  • TTY drivers;
  • UFS subsystem;
  • USB core drivers;
  • DesignWare USB3 driver;
  • USB Gadget drivers;
  • Framebuffer layer;
  • BTRFS file system;
  • File systems infrastructure;
  • EFI Variable file system;
  • Ext4 file system;
  • F2FS file system;
  • JFS file system;
  • Network file system (NFS) client;
  • Network file system (NFS) server daemon;
  • NILFS2 file system;
  • NTFS3 file system;
  • SMB network file system;
  • Asynchronous Transfer Mode (ATM) subsystem;
  • BPF subsystem;
  • NFS page cache wrapper;
  • Memory management;
  • Networking subsytem;
  • UDP network protocol;
  • Perf events;
  • RCU subsystem;
  • Tracing infrastructure;
  • 802.1Q VLAN protocol;
  • Appletalk network protocol;
  • Amateur Radio drivers;
  • B.A.T.M.A.N. meshing protocol;
  • Bluetooth subsystem;
  • Ethernet bridge;
  • Networking core;
  • HSR network protocol;
  • IPv4 networking;
  • IPv6 networking;
  • Multipath TCP;
  • Netfilter;
  • Network traffic control;
  • SCTP protocol;
  • TLS protocol;
  • Wireless networking;
  • SoC audio core drivers;
  • USB sound devices

Update instructions

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

Learn more about how to get the fixes.

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.

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

Ubuntu Release Package Version
22.04 LTS jammy linux-image-5.15.0-1101-azure-fips –  5.15.0-1101.110+fips1  
linux-image-azure-fips –  5.15.0.1101.86  
linux-image-azure-fips-5.15 –  5.15.0.1101.86  

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References

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