Nearly 380 servers in the Tor Network, 12 percent of the exit capacity, running the vulnerable version of OpenSSL could have compromised users anonymity. Intelligence agencies, including NSA, have exploited the bug to spy on communications and to steal sensitive information from affected systems. The Tor anonymity could be compromised if an attacker is able to grab encrypted information from the nodes and it it possible is they run a version of the OpenSSL library affected by Heartbleed bug. Tor Project leader Roger Dingledine, has identified and rejected 380 vulnerable exit nodes suggesting that the exit nodes should be blacklisted from the network.”]
Source: https://securityaffairs.co/wordpress/24110/hacking/heartbleed-bug-tor.html