In systemd through 233, certain sizes passed to dns_packet_new in systemd-resolved can cause it to allocate a buffer that's too small. A malicious DNS server can exploit this via a response with a specially crafted TCP payload to trick systemd-resolved into allocating a buffer that's too small, and subsequently write arbitrary data beyond the end of it.

systemd-resolved through 233 allows remote attackers to cause a denial of service (daemon crash) via a crafted DNS response with an empty question section.

The manager_invoke_notify_message function in systemd 231 and earlier allows local users to cause a denial of service (assertion failure and PID 1 hang) via a zero-length message received over a notify socket.

systemd, when updating file permissions, allows local users to change the permissions and SELinux security contexts for arbitrary files via a symlink attack on unspecified files.