CVE ID:	CVE-2021-3493
Description:	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.
Test IDs:	1.3.6.1.4.1.25623.1.0.844910
Cross References:	Common Vulnerability Exposure (CVE) ID: CVE-2021-3493 http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52 https://ubuntu.com/security/notices/USN-4917-1 https://ubuntu.com/security/notices/USN-4917-1 https://www.openwall.com/lists/oss-security/2021/04/16/1 https://www.openwall.com/lists/oss-security/2021/04/16/1