Multiple vulnerabilities has been discovered and corrected in libxml2:

Off-by-one error in libxml allows remote attackers to execute arbitrary
code or cause a denial of service (heap-based buffer overflow and
application crash) via a crafted web site CVE-2011-0216).

libxml2 allows remote attackers to cause a denial of service
(out-of-bounds read) via unspecified vectors (CVE-2011-3905).

The updated packages have been patched to correct these issues.