libxslt is a library for transforming XML files into other textual formats using the standard XSLT stylesheet transformation mechanism. A heap-based buffer overflow flaw was found in the way libxslt applied templates to nodes selected by certain namespaces. An attacker could use this flaw to create a malicious XSL file that, when used by an application linked against libxslt to perform an XSL transformation, could cause the application to crash or, possibly, execute arbitrary code with the privileges of the user running the application. Several denial of service flaws were found in libxslt. An attacker could use these flaws to create a malicious XSL file that, when used by an application linked against libxslt to perform an XSL transformation, could cause the application to crash. An information leak could occur if an application using libxslt processed an untrusted XPath expression, or used a malicious XSL file to perform an XSL transformation. If combined with other flaws, this leak could possibly help an attacker bypass intended memory corruption protections. All libxslt users are advised to upgrade to these updated packages, which contain backported patches to resolve these issues. All running applications linked against libxslt must be restarted for this update to take effect.