It was discovered that libxml2 did not correctly handle root XML document element DTD definitions. If a user were tricked into processing a specially crafted XML document, a remote attacker could cause the application linked against libxml2 to crash, leading to a denial of service. It was discovered that libxml2 did not correctly parse Notation and Enumeration attribute types. If a user were tricked into processing a specially crafted XML document, a remote attacker could cause the application linked against libxml2 to crash, leading to a denial of service. USN-644-1 fixed a vulnerability in libxml2. This advisory provides the corresponding update for Ubuntu 9.04. Original advisory details: It was discovered that libxml2 did not correctly handle long entity names. If a user were tricked into processing a specially crafted XML document, a remote attacker could execute arbitrary code with user privileges or cause the application linked against libxml2 to crash, leading to a denial of service