In FreeBSD 13.0-STABLE before n246941-20f96f215562 12.2-STABLE before r370400 11.4-STABLE before r370399 13.0-RELEASE before p4 12.2-RELEASE before p10 and 11.4-RELEASE before p13 certain VirtIO-based device models in bhyve failed to handle errors when fetching I/O descriptors. A malicious guest may cause the device model to operate on uninitialized I/O vectors leading to memory corruption crashing of the bhyve process and possibly arbitrary code execution in the bhyve process.