Heap-based buffer overflow in the ParseValue function in lexer.c in tidy before 4.9.31 allows remote attackers to cause a denial of service (crash) via vectors involving a command character in an href.
http://lists.apple.com/archives/security-announce/2015/Sep/msg00001.html
http://lists.apple.com/archives/security-announce/2015/Sep/msg00005.html
http://lists.apple.com/archives/security-announce/2015/Sep/msg00008.html
https://github.com/htacg/tidy-html5/issues/217
https://support.apple.com/HT205212
https://support.apple.com/HT205213
https://support.apple.com/HT205267
http://www.debian.org/security/2015/dsa-3309
http://www.openwall.com/lists/oss-security/2015/06/04/2
http://www.openwall.com/lists/oss-security/2015/07/13/7
http://www.openwall.com/lists/oss-security/2015/07/15/3