      cb: (err) => {
        if (err) {
          cb && cb(err);
        } else if (overflow) {
          this.write(handle,
                     buf,
                     off + len,
                     overflow,
                     origPosition + len,
                     cb);
        } else {
          cb && cb(undefined, off + len);
        }
      }
    };

    const isBuffered = sendOrBuffer(this, out);
    this._debug && this._debug(
      `SFTP: Outbound: ${isBuffered ? 'Buffered' : 'Sending'} WRITE`
    );
  }
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.