USN-7861-5: Linux kernel vulnerabilities
Ubuntu ServerCanonical
USN-7861-5: Linux kernel vulnerabilities
Publication date: 3 December 2025
Overview: Several security issues were fixed in the Linux kernel.
Packages
- linux-raspi - Linux kernel for Raspberry Pi systems
- linux-raspi-realtime - Linux kernel for Raspberry Pi Real-time systems
- linux-xilinx - Linux kernel for Xilinx systems
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:
HSI subsystem;
Bluetooth subsystem;
Timer subsystem
Update instructions
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.
The problem can be corrected by updating your system to the following package versions:
24.04 LTS noble
- linux-image-6.8.0-1019-xilinx – 6.8.0-1019.20
- linux-image-6.8.0-1042-raspi – 6.8.0-1042.46
- linux-image-6.8.0-2033-raspi-realtime – 6.8.0-2033.34
- linux-image-raspi – 6.8.0-1042.46
- linux-image-raspi-6.8 – 6.8.0-1042.46
- linux-image-raspi-realtime – 6.8.0-2033.34
- linux-image-raspi-realtime-6.8 – 6.8.0-2033.34
- linux-image-xilinx – 6.8.0.1019.20
- linux-image-xilinx-6.8 – 6.8.0.1019.20
- linux-image-xilinx-zynqmp – 6.8.0.1019.20
