dbus -- multiple vulnerabilities

Simon McVittie reports:

Alban Crequy at Collabora Ltd. discovered a bug in dbus-daemon’s
support for file descriptor passing. A malicious process could
force system services or user applications to be disconnected
from the D-Bus system bus by sending them a message containing
a file descriptor, then causing that file descriptor to exceed
the kernel’s maximum recursion depth (itself introduced to fix
a DoS) before dbus-daemon forwards the message to the victim
process. Most services and applications exit when disconnected
from the system bus, leading to a denial of service.
Additionally, Alban discovered that bug fd.o#79694, a bug
previously reported by Alejandro Martínez Suárez which was n
believed to be security flaw, could be used for a similar denial
of service, by causing dbus-daemon to attempt to forward invalid
file descriptors to a victim process when file descriptors become
associated with the wrong message.