Rauli Kaksonen, Tero Rontti and Jukka Taimisto discovered several vulnerabilities in libxml2, a library for parsing and handling XML data files, which can lead to denial of service conditions or possibly arbitrary code execution in the application using the library. The Common Vulnerabilities and Exposures project identifies the following problems: An XML document with specially-crafted Notation or Enumeration attribute types in a DTD definition leads to the use of a pointers to memory areas which have already been freed . Missing checks for the depth of ELEMENT DTD definitions when parsing child content can lead to extensive stack-growth due to a function recursion which can be triggered via a crafted XML document . For the oldstable distribution , this problem has been fixed in version 2.6.27.dfsg-6+etch1. For the stable distribution , this problem has been fixed in version 2.6.32.dfsg-5+lenny1. For the testing and unstable distribution, this problem will be fixed soon. We recommend that you upgrade your libxml2 packages.