Xen Project released a maintenance update for its popular hypervisor software on Tuesday. The company acknowledged what it called an oversight and attempted to explain what went wrong. Xen detected the missing patches before the release, but it was too late to correct the error. The two vulnerabilities that are not fixed with the maintenance release version 4.6.1 were discovered late last year. The vulnerabilities were discovered on Thursday, before the official release on Monday, according to the Xen blog.
Source: https://threatpost.com/xen-project-explains-patch-snafu/116299/