The libxml2 library is a development toolbox providing the implementation of various XML standards. One of those standards is the XML Path Language , which is a language for addressing parts of an XML document. An off-by-one error, leading to a heap-based buffer overflow, was found in the way libxml2 parsed certain XML files. A remote attacker could provide a specially-crafted XML file that, when opened in an application linked against libxml2, would cause the application to crash or, potentially, execute arbitrary code with the privileges of the user running the application. An integer overflow flaw, leading to a heap-based buffer overflow, was found in the way libxml2 parsed certain XPath expressions. If an attacker were able to supply a specially-crafted XML file to an application using libxml2, as well as an XPath expression for that application to run against the crafted file, it could cause the application to crash or, possibly, execute arbitrary code. Multiple flaws were found in the way libxml2 parsed certain XPath expressions. If an attacker were able to supply a specially-crafted XML file to an application using libxml2, as well as an XPath expression for that application to run against the crafted file, it could cause the application to crash. Note: Red Hat does not ship any applications that use libxml2 in a way that would allow the CVE-2011-1944, CVE-2010-4008, CVE-2010-4494, CVE-2011-2821, and CVE-2011-2834 flaws to be exploited; however, third-party applications may allow XPath expressions to be passed which could trigger these flaws. Red Hat would like to thank the Google Security Team for reporting the CVE-2010-4008 issue. Upstream acknowledges Bui Quang Minh from Bkis as the original reporter of CVE-2010-4008. This update also fixes the following bugs: * A number of patches have been applied to harden the XPath processing code in libxml2, such as fixing memory leaks, rounding errors, XPath numbers evaluations, and a potential error in encoding conversion. All users of libxml2 are advised to upgrade to these updated packages, which contain backported patches to correct these issues. The desktop must be restarted for this update to take effect.