In the Linux kernel, following vulnerability has been resolved: vhost-scsi: protect vq->log_used with vq->mutex The vhost-scsi completion path may access vq->log_base when is already set to false. vhost-thread QEMU-thread vhost_scsi_complete_cmd_work() -> vhost_add_used() -> vhost_add_used_n() if (unlikely(vq->log_used)) QEMU disables vq->log_used via VHOST_SET_VRING_ADDR. mutex_lock(&vq->mutex); = false now! mutex_unlock(&vq->mutex); gfree(vq->log_base) log_used() log_write(vq->log_base) Assuming VMM is QEMU. The from userpace and can be reclaimed gfree(). As a result, this causes invalid memory writes to QEMU userspace. The control queue same issue.