Malicious software running in a guest VM can exploit the buffer overflow to achieve code execution on the host in the bhyve userspace process, which typically runs as root. Note that bhyve runs in a Capsicum sandbox, so malicious code is constrained by the capabilities available to the bhyve process.
https://security.netapp.com/advisory/ntap-20240920-0009/
https://security.freebsd.org/advisories/FreeBSD-SA-24:10.bhyve.asc