GNU Emacs before 25.3 allows remote attackers to execute arbitrary code via email with crafted “Content-Type: text/enriched” data containing an x-display XML element that specifies execution of shell commands, related to an unsafe text/enriched extension in lisp/textmodes/enriched.el, and unsafe Gnus support for enriched and richtext inline MIME objects in lisp/gnus/mm-view.el. In particular, an Emacs user can be instantly compromised by reading a crafted email message (or Usenet news article).
www.debian.org/security/2017/dsa-3975
www.openwall.com/lists/oss-security/2017/09/11/1
access.redhat.com/errata/RHSA-2017:2771
debbugs.gnu.org/cgi/bugreport.cgi?bug=28350
git.savannah.gnu.org/cgit/emacs.git/commit/?h=emacs-25&id=9ad0fcc54442a9a01d41be19880250783426db70
security.gentoo.org/glsa/201801-07
www.debian.org/security/2017/dsa-3970
www.gnu.org/software/emacs/index.html#Releases