A memory leak was discovered in the backport of fixes for CVE-2018-16864 in Red Hat Enterprise Linux (since version v219-62.2) and CentOS. Function dispatchmessagereal() in journald-server.c does not free the memory allocated by setiovecfieldfree() to store the CMDLINE= entry. A local attacker may use this flaw to make systemd-journald crash.
However systemd-journald crash is automatically restarted by systemd by default.