In tnef before 1.4.18, an attacker may be able to write to the victim's .ssh/authorized_keys file via an e-mail message with a crafted winmail.dat application/ms-tnef attachment, because of a heap-based buffer over-read involving strdup.

Affected: Ubuntu:16.04:LTS: tnef

Paul Dreik discovered that TNEF incorrectly handled filenames. If a user were tricked into opening a specially crafted email attachment, an attacker could possibly use this issue to write arbitrary files to the filesystem or cause TNEF crash, resulting in a denial of service. (CVE-2019-18849)