If you're performing a fresh Oracle Linux 9.6 installation from an ISO image, then after the installation completes, the UEK R8 kernel is automatically enabled.

UEK R8 includes many new features including security and performance enhancements. For more details, see Unbreakable Enterprise Kernel 8: Release Notes (6.12.0-0.20.20).

If you select RHCK as the default kernel instead of UEK, ensure that you disable UEK yum repositories or ULN channels. For more information about switching to RHCK, see Oracle Linux 9: Managing Kernels and System Boot.

In the case of updates, switching to UEK R8 isn't automatic. If you're upgrading from a prior update release of Oracle Linux 9, the system continues to run with the kernel that's already installed.

If the system is using UEK R7, you can upgrade to UEK R8 by using the following instructions:

• Updating by using yum

  When you update to Oracle Linux 9.6, the previous kernel is preserved. At the same time, the UEK R8 yum repository is also added to the system yum configuration. To move to the latest kernel, run the following commands, depending on the system platform:

  • On x86_64 systems:

    sudo dnf config-manager --disable ol9_UEKR7
    sudo dnf config-manager --enable ol9_UEKR8
    sudo dnf install -y kernel-uek
    sudo dnf update

  • On aarch64 systems:

    sudo dnf config-manager -enable ol9_UEKR8
    sudo dnf install -y kernel-uek
    sudo dnf update

• Updating by using ULN

  Similar to the previous scenario, the previous kernel is preserved. However, system subscriptions might change as a result. Sign in to https://linux.oracle.com, and update the system channel subscriptions to enable the ol9_x86_64_UEKR8 or ol9_aarch64_UEKR8, as required. After you have updated the system channel subscriptions, run:

  sudo dnf install -y kernel-uek
  sudo dnf update

After setting the default kernel, you can further configure kernel boot parameters so that these parameters are applied at every system boot. For instructions, see Oracle Linux 9: Managing Kernels and System Boot.

The GRUB bootloader is updated for security enhancements in Oracle Linux 9.6.

Several CVEs are resolved, including issues such as:

• Heap out-of-bounds (OOB) writes during JPEG parsing
• Missing checks for failed allocations
• Integer overflows resulting in heap-based OOB writes and reads
• Use-after-free errors due to hooks not being removed on module unload
• OOB writes in configuration file parsing

Oracle Linux image builder has been updated to support creating disk images with custom partitioning layouts. This includes the ability to create custom mountpoints, LVM-based partitions, and LVM-based SWAP configurations using a blueprint file.