A NULL pointer dereference issue was found in the ACPI code of QEMU. A malicious, privileged user within the guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition.
https://www.mail-archive.com/qemu-devel%40nongnu.org/msg857944.html
https://gitlab.com/qemu-project/qemu/-/issues/770
https://gitlab.com/qemu-project/qemu/-/commit/9bd6565ccee68f72d5012e24646e12a1c662827e