The Bzrtp library (aka libbzrtp) 1.0.x before 1.0.4 allows man-in-the-middle attackers to conduct spoofing attacks by leveraging a missing HVI check on DHPart2 packet reception.
https://github.com/gteissier/CVE-2016-6271
https://github.com/BelledonneCommunications/bzrtp/commit/bbb1e6e2f467ee4bd7b9a8c800e4f07343d7d99b