activerecord/lib/active_record/nested_attributes.rb in Active Record in Ruby on Rails 3.1.x and 3.2.x before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, and 5.x before 5.0.0.beta1.1 does not properly implement a certain destroy option, which allows remote attackers to bypass intended change restrictions by leveraging use of the nested attributes feature.
https://groups.google.com/forum/message/raw?msg=ruby-security-ann/cawsWcQ6c8g/LATIsglZEgAJ
http://www.securitytracker.com/id/1034816
http://www.securityfocus.com/bid/81806
http://www.openwall.com/lists/oss-security/2016/01/25/10
http://www.debian.org/security/2016/dsa-3464
http://rhn.redhat.com/errata/RHSA-2016-0296.html
http://lists.opensuse.org/opensuse-updates/2016-02/msg00043.html
http://lists.opensuse.org/opensuse-updates/2016-02/msg00034.html
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00053.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-February/178065.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-February/178041.html