This firmware is known to be vulnerable.
OLD PEOPLE (apologies for the political incorrectness) + VULNERABLE FIRMWARE =
Not for long...
I beg you to consider upgrading...is it a old (or proprietary) driver issue???
To your question...Do you mean get into the router without the password?
If you mean a firmware with custom default configs, please consider version 17.04.5 or 18.06.0.
EDIT:
See:
Also, there are issues building old firmware on newer systems: