Hi there,
we have just released version 1705.02 of the official CentOS Linux images for Vagrant (centos/6 and centos/7) on Atlas. This update contains the security fixes for the "stack clash" vulnerability.
https://access.redhat.com/security/vulnerabilities/stackguard https://blog.qualys.com/securitylabs/2017/06/19/the-stack-clash
Existing images can be upgraded in-place via "sudo yum update".
Best regards, Laurențiu