parser.c in libxml2 before 2.9.2 does not properly prevent entity expansion even when entity substitution has been disabled, which allows context-dependent attackers to cause a denial of service (CPU consumption) via a crafted XML document containing a large number of nested entity references, a variant of the billion laughs attack.<a href=http://cwe.mitre.org/data/definitions/611.html target=_blank>CWE-611: Improper Restriction of XML External Entity Reference ('XXE')</a> http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-3660