In ISC DHCP 1.0 -> 4.4.3, ISC DHCP 4.1-ESV-R1 -> 4.1-ESV-R16-P1 a system with access to a DHCP server, sending DHCP packets crafted to include fqdn labels longer than 63 bytes, could eventually cause the server to run out of memory.
https://security.gentoo.org/glsa/202305-22
https://lists.debian.org/debian-lts-announce/2022/10/msg00015.html