[ANN] nokogiri security update - 1.6.7.1

Hello,

Nokogiri version 1.6.7.1 has been released, pulling in several upstream
patches to the vendored libxml2 to address the following CVEs:

  CVE-2015-5312
  CVE-2015-7497
  CVE-2015-7498
  CVE-2015-7499
  CVE-2015-7500
  CVE-2015-8241
  CVE-2015-8242
  CVE-2015-8317

These CVEs are all *low* or *medium* priority according to Canonical,
however NIST NVD gives CVE-2015-5312 a *high* severity score. Full details
are included below.

*Vulnerable versions:* Nokogiri >= 1.6.0, <= 1.6.7; only affects
installations using the vendored libxml2.

*Recommended action: *upgrade to 1.6.7.1

*Full CVE information:*

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-5312

  Original release date: 12/15/2015
  CVSS v2 Base Score: 7.1 (HIGH)

  The xmlStringLenDecodeEntities function in parser.c in libxml2
  before 2.9.3 does not properly prevent entity expansion, which
  allows context-dependent attackers to cause a denial of
  service (CPU consumption) via crafted XML data, a different
  vulnerability than CVE-2014-3660.

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-7497

  Original release date: 12/15/2015
  CVSS v2 Base Score: 5.0 (MEDIUM)

  Heap-based buffer overflow in the xmlDictComputeFastQKey
  function in dict.c in libxml2 before 2.9.3 allows
  context-dependent attackers to cause a denial of service via
  unspecified vectors.

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-7498

  Original release date: 12/15/2015
  CVSS v2 Base Score: 5.0 (MEDIUM)

  Heap-based buffer overflow in the xmlParseXmlDecl function in
  parser.c in libxml2 before 2.9.3 allows context-dependent
  attackers to cause a denial of service via unspecified vectors
  related to extracting errors after an encoding conversion
  failure.

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-7499

  Original release date: 12/15/2015
  CVSS v2 Base Score: 5.0 (MEDIUM)

  Heap-based buffer overflow in the xmlGROW function in parser.c
  in libxml2 before 2.9.3 allows context-dependent attackers to
  obtain sensitive process memory information via unspecified
  vectors.

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-7500

  Original release date: 12/15/2015
  CVSS v2 Base Score: 5.0 (MEDIUM)

  The xmlParseMisc function in parser.c in libxml2 before 2.9.3
  allows context-dependent attackers to cause a denial of
  service (out-of-bounds heap read) via unspecified vectors
  related to incorrect entities boundaries and start tags.

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-8241

  Original release date: 12/15/2015
  CVSS v2 Base Score: 6.4 (MEDIUM)

  The xmlNextChar function in libxml2 2.9.2 does not properly
  check the state, which allows context-dependent attackers to
  cause a denial of service (heap-based buffer over-read and
  application crash) or obtain sensitive information via crafted
  XML data.

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-8242

  Original release date: 12/15/2015
  CVSS v2 Base Score: 5.8 (MEDIUM)

  The xmlSAX2TextNode function in SAX2.c in the push interface in
  the HTML parser in libxml2 before 2.9.3 allows
  context-dependent attackers to cause a denial of
  service (stack-based buffer over-read and application crash) or
  obtain sensitive information via crafted XML data.

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-8317

  Original release date: 12/15/2015
  CVSS v2 Base Score: 5.0 (MEDIUM)

  The xmlParseXMLDecl function in parser.c in libxml2 before
  2.9.3 allows context-dependent attackers to obtain sensitive
  information via an (1) unterminated encoding value or (2)
  incomplete XML declaration in XML data, which triggers an
  out-of-bounds heap read.