CVE-2020-8832: 
Linux Kernel vulnerability analysis and mitigation

CVE-2020-8832 is a vulnerability discovered in the Linux kernel affecting Ubuntu 18.04 LTS systems before version 4.15.0-91.92. The issue stems from an incomplete fix for a previous vulnerability (CVE-2019-14615) related to improper clearing of data structures on context switches for certain Intel graphics processors (Ubuntu USN, NVD).

The vulnerability is characterized by a CVSS v3.1 Base Score of 5.5 (Medium) with a vector string of CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N. The issue specifically affects the DRM subsystem and i915 driver, requiring commit d2b4b97933f5 ("drm/i915: Record the default hw state after reset upon load") and its prerequisites to fully fix the vulnerability in 4.15-based kernels (Launchpad Bug).

When successfully exploited, this vulnerability could allow a local attacker to expose sensitive information. The vulnerability specifically affects systems running Ubuntu 18.04 LTS with kernel versions prior to 4.15.0-91.92, while other versions such as Xenial (4.4), Disco (5.0), Eoan (5.3), and Focal (5.4) are not affected by this incomplete fix issue (NetApp Advisory).

The vulnerability was addressed in Ubuntu 18.04 LTS with the release of kernel version 4.15.0-91.92. Users are advised to update their systems to this version or later. The fix includes several patches to the DRM subsystem and i915 driver to properly handle context state and hardware initialization (Ubuntu USN).