4.98. libxml2

Updated libxml2 packages that fix several security issues are now available for Red Hat Enterprise Linux 5.
The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links associated with each description below.
The libxml2 library is a development toolbox providing the implementation of various XML standards. One of those standards is the XML Path Language (XPath), which is a language for addressing parts of an XML document.

Security Fixes

CVE-2011-3919
A heap-based buffer overflow flaw was found in the way libxml2 decoded entity references with long names. 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.
CVE-2011-0216
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.
CVE-2011-1944
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.
CVE-2010-4008, CVE-2011-2834
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.
CVE-2011-3905
An out-of-bounds memory read flaw was found in libxml2. 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.

Note

Red Hat does not ship any applications that use libxml2 in a way that would allow the CVE-2011-1944, CVE-2010-4008, 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.
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 (log out, then log back in) for this update to take effect.
Updated libxml2 packages that resolve an issue are now available for Red Hat Enterprise Linux 5.
The libxml2 library provides a development tool to manipulate XML and HTML files. The library also implements various XML and HTML standards. One of those standards is XML Schemas which allows validation of the content of an XML document.

Bug Fix

BZ#747865
The libxml2 XML Schemas implementation allowed empty values for integer fields using, for example, the predefined schemas type, xsd:byte. This led to unwanted validation of documents that were invalid per these schemas. The implementation has been modified to forbid those empty integer values, and all documents containing such values will now fail the XML Schemas validation.
All users of libxml2 are advised to upgrade to these updated packages, which fix this bug.