The Samba vfs_fruit module uses extended file attributes (EA, xattr) to provide "...enhanced compatibility with Apple SMB clients and interoperability with a Netatalk 3 AFP fileserver." Samba versions prior to 4.13.17, 4.14.12 and 4.15.5 with vfs_fruit configured allow out-of-bounds heap read and write via specially crafted extended file attributes. A remote attacker with write access to extended file attributes can execute arbitrary code with the privileges of smbd, typically root.
https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-207a
https://www.samba.org/samba/security/CVE-2021-44142.html
https://security.gentoo.org/glsa/202309-06