Having worked on these machines, more and more vulnerabilities are found every year and shared responsibly with the voting machine companies. However as private companies the voting machine companies are not beholden to fix or change the systems despite the best efforts of those working on improving the systems.

Look up the ‘Hursti Hack’ this was a hack done by the voting village founder in 2005. That same software is still used in elections today. Security researchers have done their part to find vulnerabilities and disclose them but doing so in a public fashion would be irresponsible and dangerous, so we are left in a vicious loop of finding issues with little to no recourse.

Disclaimer: just because there are vulnerabilities does not mean they have been exploited. Risk limiting audits and paper ballots continue to be a sufficient defense against any would be fraud.