Nokogiri gem, via libxml, is affected by DoS and RCE vulnerabilities

The version of libxml2 packaged with Nokogiri contains several
vulnerabilities. Nokogiri has mitigated these issues by upgrading to
libxml 2.9.5.

It was discovered that a type confusion error existed in libxml2. An
attacker could use this to specially construct XML data that
could cause a denial of service or possibly execute arbitrary
code. (CVE-2017-0663)

It was discovered that libxml2 did not properly validate parsed entity
references. An attacker could use this to specially construct XML
data that could expose sensitive information. (CVE-2017-7375)

It was discovered that a buffer overflow existed in libxml2 when
handling HTTP redirects. An attacker could use this to specially
construct XML data that could cause a denial of service or possibly
execute arbitrary code. (CVE-2017-7376)

Marcel Böhme and Van-Thuan Pham discovered a buffer overflow in
libxml2 when handling elements. An attacker could use this to specially
construct XML data that could cause a denial of service or possibly
execute arbitrary code. (CVE-2017-9047)

Marcel Böhme and Van-Thuan Pham discovered a buffer overread
in libxml2 when handling elements. An attacker could use this
to specially construct XML data that could cause a denial of
service. (CVE-2017-9048)

Marcel Böhme and Van-Thuan Pham discovered multiple buffer overreads
in libxml2 when handling parameter-entity references. An attacker
could use these to specially construct XML data that could cause a
denial of service. (CVE-2017-9049, CVE-2017-9050)