On Ubuntu kernels carrying both c914c0e27eb0 and "UBUNTU: SAUCE: overlayfs: Skip permission checking for trusted.overlayfs.* xattrs", an unprivileged user may set privileged extended attributes on the mounted files, leading them to be set on the upper files without the appropriate security checks.
4.13.0-16.195.13.0-19.196.8.0-31.313.11.0-12.194.2.0-16.194.2.0-17.214.2.0-19.234.3.0-1.104.3.0-2.114.3.0-5.164.3.0-6.174.3.0-7.184.4.0-2.166.5.0-9.95.3.0-18.195.3.0-24.265.4.0-9.125.3.0-1003.35.3.0-1008.95.3.0-1009.105.3.0-1010.115.4.0-1005.55.13.0-1005.64.4.0-1001.10Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:HI:HA:HCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H