It has happened in the past (chosen example: 2014). Not sure if any current vulnerability is public. https://blog.torproject.org/tor-security-advisory-relay-ea

It has happened in the past (chosen example: 2014). Not sure if any current vulnerability is public. https://blog.torproject.org/tor-security-advisory-relay-early-traffic-confirmation-attack https://blog.torproject.org/tor-security-advisory-relay-earl... https://blog.torproject.org/did-fbi-pay-university-attack-tor-users https://blog.torproject.org/did-fbi-pay-university-attack-to...