In ytnef 1.9.2, a heap-based buffer overflow vulnerability was found in the function TNEFFillMapi in ytnef.c, which allows attackers to cause a denial of service via a crafted file.
https://usn.ubuntu.com/3667-1/
https://somevulnsofadlab.blogspot.com/2017/07/ytnefheap-buffer-overflow-in.html