CVE-2023-6931: 
Linux Kernel vulnerability analysis and mitigation

A heap out-of-bounds write vulnerability was discovered in the Linux kernel's Performance Events system component (CVE-2023-6931). The vulnerability was disclosed on December 19, 2023, affecting Linux kernel versions from 4.3 up to (excluding) 6.7. The issue occurs when a perfevent's readsize can overflow, leading to a heap out-of-bounds increment or write in perfreadgroup() (Kernel Patch).

The vulnerability stems from perfeventvalidatesize() only checking the size of the newly added event, even though the sizes of all existing events can also change due to not all events having the same readformat. The issue is triggered when attaching a new event through perfgroupattach(), which re-computes the size for all events. The vulnerability has been assigned a CVSS v3.1 base score of 7.0 (High) with vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD).

The vulnerability can be exploited to achieve local privilege escalation. When successfully exploited, it allows an attacker to cause a denial of service (crash or memory corruption) or potentially execute arbitrary code with elevated privileges (Debian LTS).

The vulnerability has been fixed in Linux kernel commit 382c27f4ed28f803b1f1473ac2d8db0afc795a1b. Users are recommended to upgrade their systems to kernel versions that include this fix. Various distributions have released security updates to address this vulnerability, including Debian, Ubuntu, and others (NVD, Debian LTS).