Over the past several weeks, there has been considerable interest in a series of vulnerabilities in bash with the attention grabbing name of "shellshock". These bash vulnerabilities are more properly known as CVE-2014-6271, CVE-2014-6277, CVE-2014-6278, CVE-2014-7169, CVE-2014-7186 and CVE-2014-7187. As was indicated in security bulletin CTX200217, XenServer hosts were potentially impacted, but investigation was continuing. That investigation has been completed and the associated impact is described in security bulletin CTX200223, which also contains patch information for these vulnerabilities.
Learning about new XenServer hotfixes
When a hotfix is released for XenServer, it will be posted to the Citrix support web site. You can receive alerts from the support site by registering at http://support.citrix.com/profile/watches and following the instructions there. You will need to create an account if you don't have one, but the account is completely free. Whenever a hotfix is released, there will be an accompanying security advisory in the form of a CTX knowledgebase article for it, and those same KB articles will be linked on xenserver.org in the download page.
Patching XenServer hosts
XenServer admins are encouraged to schedule patching of their XenServer installations. Please note that the items contained in the CTX200223 bulletin do impact XenServer 6.2 hosts, and to apply the patch, all XenServer 6.2 hosts will first need to be patched to service pack 1. The complete list of patches can be found on the XenServer download page.