# Chef Client 12.21.26 released

**URL:** <https://discourse.chef.io/t/chef-client-12-21-26-released/11840>\
**Category:** Chef Release Announcements\
**Created:** [October 30, 2017, 6:55pm UTC](https://discourse.chef.io/t/chef-client-12-21-26-released/11840 "2017-10-30T18:55:10Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![tas50](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.chef.io/tas50/32/941_2.png) [@tas50](https://discourse.chef.io/u/tas50)\
**Post date:** [October 30, 2017, 6:55pm UTC](https://discourse.chef.io/t/chef-client-12-21-26-released/11840/1 "2017-10-30T18:55:10Z")

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Hey Everyone,

Happy Monday and to celebrate we’ve released a new version of Chef 12 chock-full of security updates as well as some new functionality.

## Ohai 8.25 with Critical Plugins Functionality

Users can now specify a list of plugins which are `critical` for the Chef run. Critical plugins will cause Ohai to fail if they do not run successfully (and thus cause a Chef run using Ohai to fail). The syntax for this is:

```auto
ohai.critical_plugins << :Filesystem

```

## Security Updates

We’ve updated multiple libraries to resolve CVEs:

### libxml2 upgraded to 2.9.5

- [https://www.cvedetails.com/cve/CVE-2017-9050/](https://www.cvedetails.com/cve/CVE-2017-9050/)
- [https://www.cvedetails.com/cve/CVE-2017-9049/](https://www.cvedetails.com/cve/CVE-2017-9049/)
- [https://www.cvedetails.com/cve/CVE-2017-9048/](https://www.cvedetails.com/cve/CVE-2017-9048/)
- [https://www.cvedetails.com/cve/CVE-2017-9047/](https://www.cvedetails.com/cve/CVE-2017-9047/)
- [https://www.cvedetails.com/cve/CVE-2017-8872/](https://www.cvedetails.com/cve/CVE-2017-8872/)
- [https://www.cvedetails.com/cve/CVE-2017-5969/](https://www.cvedetails.com/cve/CVE-2017-5969/)
- [https://www.cvedetails.com/cve/CVE-2016-9318/](https://www.cvedetails.com/cve/CVE-2016-9318/)
- [https://www.cvedetails.com/cve/CVE-2016-5131/](https://www.cvedetails.com/cve/CVE-2016-5131/)

### libxlst upgraded to 1.1.30

- [http://www.cvedetails.com/cve/CVE-2017-5029/](http://www.cvedetails.com/cve/CVE-2017-5029/)
- [http://www.cvedetails.com/cve/CVE-2015-9019/](http://www.cvedetails.com/cve/CVE-2015-9019/)

### zlib upgraded to 1.2.11

- [https://www.cvedetails.com/cve/CVE-2016-9840/](https://www.cvedetails.com/cve/CVE-2016-9840/)
- [https://www.cvedetails.com/cve/CVE-2016-9841/](https://www.cvedetails.com/cve/CVE-2016-9841/)
- [https://www.cvedetails.com/cve/CVE-2016-9842/](https://www.cvedetails.com/cve/CVE-2016-9842/)
- [https://www.cvedetails.com/cve/CVE-2016-9843/](https://www.cvedetails.com/cve/CVE-2016-9843/)

### openssl upgraded to 1.0.2j

- [http://www.cvedetails.com/cve/CVE-2017-3731](http://www.cvedetails.com/cve/CVE-2017-3731)
- [http://www.cvedetails.com/cve/CVE-2017-3732](http://www.cvedetails.com/cve/CVE-2017-3732)
- [http://www.cvedetails.com/cve/CVE-2016-7055](http://www.cvedetails.com/cve/CVE-2016-7055)

### rubygems upgraded to 2.6.14

- [http://www.cvedetails.com/cve/CVE-2017-0903](http://www.cvedetails.com/cve/CVE-2017-0903)

## Full Ruby 2.2 support restored

The previous release of Chef 12.21.20 introduced an Ruby 2.2 incompatibility in Windows DSC code handling that has been resolved.