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.
https://securelist.com/vulnerability-exploit-report-q2-2024/113455/
https://wiz.io/blog/ubuntu-overlayfs-vulnerability
https://ubuntu.com/security/notices/USN-6250-1
https://lists.ubuntu.com/archives/kernel-team/2023-July/140923.html
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-2640