A NULL pointer dereference vulnerability exists in the xpath.c:xmlXPathCompOpEval function of libxml2 through 2.9.8 when parsing an invalid XPath expression in the XPATH_OP_AND or XPATH_OP_OR case. Applications processing untrusted XSL format inputs with the use of the libxml2 library may be vulnerable to a denial of service attack due to a crash of the application. Use after free in libxml2 before 2.9.5, as used in Google Chrome prior to 63.0.3239.84 and other products, allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. A denial of service flaw was found in libxml2. A remote attacker could provide a specially crafted XML or HTML file that, when processed by an application using libxml2, would cause that application to crash. libxml2 2.9.8, if --with-lzma is used, allows remote attackers to cause a denial of service via a crafted XML file that triggers LZMA_MEMLIMIT_ERROR, as demonstrated by xmllint, a different vulnerability than CVE-2015-8035 and CVE-2018-9251 . The xz_head function in xzlib.c in libxml2 before 2.9.6 allows remote attackers to cause a denial of service via a crafted LZMA file, because the decoder functionality does not restrict memory usage to what is required for a legitimate file. Use-after-free vulnerability in libxml2 through 2.9.4, as used in Google Chrome before 52.0.2743.82, allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors related to the XPointer range-to function