USN-7940-1: Linux kernel (Azure FIPS) vulnerabilities

USN-7940-1: Linux kernel (Azure FIPS) vulnerabilities

Publication date: 17 December 2025
Overview: Several security issues were fixed in the Linux kernel.

Packages
linux-azure-fips - Linux kernel for Microsoft Azure Cloud systems with FIPS

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:

• ARM64 architecture;
• PowerPC architecture;
• x86 architecture;
• Cryptographic API;
• ACPI drivers;
• Ublk userspace block driver;
• Clock framework and drivers;
• EDAC drivers;
• GPU drivers;
• HSI subsystem;
• IIO subsystem;
• InfiniBand drivers;
• Media drivers;
• MemoryStick subsystem;
• Network drivers;
• NTB driver;
• PCI subsystem;
• Remote Processor subsystem;
• Thermal drivers;
• Virtio Host (VHOST) subsystem;
• 9P distributed file system;
• File systems infrastructure;
• JFS file system;
• Network file system (NFS) server daemon;
• NTFS3 file system;
• SMB network file system;
• Memory management;
• Bluetooth subsystem;
• RDMA verbs API;
• Kernel fork() syscall;
• Timer subsystem;
• Tracing infrastructure;
• Watch queue notification mechanism;
• Appletalk network protocol;
• Asynchronous Transfer Mode (ATM) subsystem;
• Networking core;
• IPv4 networking;
• IPv6 networking;
• Netfilter;
• Network traffic control;
• SCTP protocol;
• TLS protocol;
• SoC Audio for Freescale CPUs drivers

Update instructions
After a standard system update you need to reboot your computer to make all the necessary changes.
The problem can be corrected by updating your system to the following package versions:

24.04 LTS noble

• linux-image-6.8.0-1044-azure-fips – 6.8.0-1044.50+fips1
• linux-image-azure-fips – 6.8.0-1044.50+fips1
• linux-image-azure-fips-6.8 – 6.8.0-1044.50+fips1