Use-after-free vulnerability in dns.c in Tor before 0.2.2.38 might allow remote attackers to cause a denial of service (daemon crash) via vectors related to failed DNS requests.
https://trac.torproject.org/projects/tor/ticket/6480
https://lists.torproject.org/pipermail/tor-announce/2012-August/000086.html
https://gitweb.torproject.org/tor.git/commit/62637fa22405278758febb1743da9af562524d4c
https://bugzilla.redhat.com/show_bug.cgi?id=849949
http://security.gentoo.org/glsa/glsa-201301-03.xml
http://openwall.com/lists/oss-security/2012/08/21/6
http://lists.opensuse.org/opensuse-updates/2012-08/msg00048.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-September/088006.html