Mozilla Firefox before 55.0Firefox ESR before 52.3 or Thunderbird 52.3 :- Mozilla developers and community members Masayuki Nakano, Gary Kwong, Ronald Crane, Andrew McCreight, Tyson Smith, Bevis Tseng, Christian Holler, Bryce Van Dyk, Dragana Damjanovic, Kartikaya Gupta, Philipp, Tristan Bourvon, and Andi-Bogdan Postelnicu reported memory safety bugs present in Firefox and Firefox ESR. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code.