virtio_gpu_resource_create_blob() stores the guest-controlled blob_size without checking it against the total size of the iov backing entries. Since both values are independently guest-controlled, a malicious guest can set blob_size much larger than the actual iov backing. Subsequent SET_SCANOUT_BLOB checks bounds against the inflated blob_size, allowing a pixman surface to be created over the undersized buffer. Any display refresh then reads past the actual allocation, potentially crashing QEMU or leaking host memory contents depending on the backing type.