Multiple directory traversal and buffer overflow vulnerabilities were discovered in yTNEF, and in Evolution's TNEF parser that is derived from yTNEF. A crafted email could cause these applications to write data in arbitrary locations on the filesystem, crash, or potentially execute arbitrary code when decoding attachments.
The TNEFFillMapi function in lib/ytnef.c in libytnef in ytnef through 1.9.2 does not ensure a nonzero count value before a certain memory allocation, which allows remote attackers to cause a denial of service (heap-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted tnef file.