openssl encrypt 1.4.x before 1.4.9 contains an optional D-Bus crypto service whose org.freedesktop.DBus.Properties.Set method performs neither a polkit authorization check nor value validation. Any local user on the system bus can call Set without authorization and set MaxConcurrentOperations (to 0/negative, causing the concurrency gate to refuse all subsequent operations, or to a huge value removing the limit) or the unbounded DefaultTimeout, resulting in a persistent denial of service of the root daemon. The D-Bus service exists only on the 1.4.x line and was removed in 1.5.x.