The system could be made to expose sensitive information.
Jann Horn and Ken Johnson discovered that microprocessors utilizing speculative execution of a memory read may allow unauthorized memory reads via a sidechannel attack. This flaw is known as Spectre Variant 4. A local attacker could use this to expose sensitive information, including kernel memory.
22 May 2018
A security issue affects these releases of Ubuntu and its derivatives:
The system could be made to expose sensitive information.
Jann Horn and Ken Johnson discovered that microprocessors utilizing speculative execution of a memory read may allow unauthorized memory reads via a sidechannel attack. This flaw is known as Spectre Variant 4. A local attacker could use this to expose sensitive information, including kernel memory.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
Please note that fully mitigating CVE-2018-3639 (Spectre Variant 4) may require corresponding processor microcode/firmware updates or, in virtual environments, hypervisor updates. On i386 and amd64 architectures, the SSBD feature is required to enable the kernel mitigations. BIOS vendors will be making updates available for Intel processors that implement SSBD and Ubuntu is working with Intel to provide future microcode updates. Ubuntu users with a processor from a different vendor should contact the vendor to identify necessary firmware updates. Ubuntu provided corresponding QEMU updates for users of self-hosted virtual environments in USN 3651-1. Ubuntu users in cloud environments should contact the cloud provider to confirm that the hypervisor has been updated to expose the new CPU features to virtual machines.