A tnef security update has been released for Debian GNU/Linux 8 LTS

Package : tnef
Version : 1.4.9-1+deb8u4
CVE ID : CVE-2019-18849
Debian Bug : 944851

In tnef, 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.

For Debian 8 "Jessie", this problem has been fixed in version
1.4.9-1+deb8u4.

We recommend that you upgrade your tnef packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS