function bufferSlice(buf, start, end) {
  if (end === undefined)
    end = buf.length;
  return new FastBuffer(buf.buffer, buf.byteOffset + start, end - start);
}
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.