The compressed packet parser in GnuPG 1.4.x before 1.4.15 and 2.0.x before 2.0.22 allows remote attackers to cause a denial of service (infinite recursion) via a crafted OpenPGP message.
https://bugzilla.redhat.com/show_bug.cgi?id=1015685
http://www.ubuntu.com/usn/USN-1987-1
http://www.debian.org/security/2013/dsa-2774
http://www.debian.org/security/2013/dsa-2773
http://rhn.redhat.com/errata/RHSA-2013-1459.html
http://lists.opensuse.org/opensuse-updates/2013-10/msg00025.html
http://lists.opensuse.org/opensuse-updates/2013-10/msg00020.html
http://lists.gnupg.org/pipermail/gnupg-announce/2013q4/000334.html
http://lists.gnupg.org/pipermail/gnupg-announce/2013q4/000333.html