Linux Kernel Privilege Escalation Vulnerability (CVE-2021-3493)

A local attacker, with a low-privilege account, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2022-11-10 under CISA BOD 22-01.

This is a Software Vulnerability (CWE-270) (CWE-270) vulnerability in Linux Kernel. The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges. Exploitation requires local access, low attack complexity, a low-privilege authenticated account, and no user interaction required.

Probably yes if any of these apply:

Active exploitation documented in the wild. Threat-research write-up: http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html