A denial of service vulnerability was discovered in Samba's LDAP server before versions 4.7.12, 4.8.7, and 4.9.3. A CNAME loop could lead to infinite recursion in the server. An unprivileged local attacker could create such an entry, leading to denial of service.
https://www.samba.org/samba/security/CVE-2018-14629.html
https://www.debian.org/security/2018/dsa-4345
https://usn.ubuntu.com/3827-2/
https://usn.ubuntu.com/3827-1/
https://security.netapp.com/advisory/ntap-20181127-0001/
https://security.gentoo.org/glsa/202003-52
https://lists.debian.org/debian-lts-announce/2018/12/msg00005.html