The flac_buffer_copy function in flac.c in libsndfile 1.0.28 allows remote attackers to cause a denial of service (buffer overflow and application crash) or possibly have unspecified other impact via a crafted audio file.
https://security.gentoo.org/glsa/201811-23
https://lists.debian.org/debian-lts-announce/2018/12/msg00016.html