The decode_entities function in util.c in HTML-Parser before 3.63 allows context-dependent attackers to cause a denial of service (infinite loop) via an incomplete SGML numeric character reference, which triggers generation of an invalid UTF-8 character.
https://issues.apache.org/SpamAssassin/show_bug.cgi?id=6225
https://exchange.xforce.ibmcloud.com/vulnerabilities/53941
https://bugzilla.redhat.com/show_bug.cgi?id=530604
http://www.vupen.com/english/advisories/2009/3022
http://www.securityfocus.com/bid/36807
http://www.openwall.com/lists/oss-security/2009/10/23/9
http://secunia.com/advisories/37155
http://github.com/gisle/html-parser/commit/b9aae1e43eb2c8e989510187cff0ba3e996f9a4c