Affected: RubyGems: nokogiri

### Summary

Nokogiri [v1.13.2](https://github.com/sparklemotion/nokogiri/releases/tag/v1.13.2) upgrades two of its packaged dependencies:

- vendored libxml2 from v2.9.12 to [v2.9.13](https://download.gnome.org/sources/libxml2/2.9/libxml2-2.9.13.news) - vendored libxslt from v1.1.34 to [v1.1.35](https://download.gnome.org/sources/libxslt/1.1/libxslt-1.1.35.news)

Those library versions address the following upstream CVEs:

- libxslt: [CVE-2021-30560](https://nvd.nist.gov/vuln/detail/CVE-2021-30560) (CVSS 8.8, High severity) - libxml2: [CVE-2022-23308](https://nvd.nist.gov/vuln/detail/CVE-2022-23308) (Unspecified severity, see more information below)

Those library versions also address numerous other issues including performance improvements, regression fixes, and bug fixes, as well as memory leaks and other use-after-free issues that were not assigned CVEs.

Please note that this advisory only applies to the CRuby implementation of Nokogiri `< 1.13.2`, and only if the _packaged_ libraries are being used. If you've overridden defaults at installation time to use _system_ libraries instead of packaged libraries, you should instead pay attention to your distro's `libxml2` and `libxslt` release announcements.

### Mitigation

Upgrade to Nokogiri `>= 1.13.2`.

Users who are unable to upgrade Nokogiri may also choose a more complicated mitigation: compile and link an older version Nokogiri against external libraries libxml2 `>= 2.9.13` and libxslt `>= 1.1.35`, which will also a…