Security researcher André Bargull reported non-configurable properties on JavaScript objects can be redefined while parsing JSON in violation of the ECMAScript 6 standard. This allows malicious web content to bypass same-origin policy by editing these properties to arbitrary values. External Reference: https://www.mozilla.org/security/announce/2015/mfsa2015-82.html Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges André Bargull as the original reporter.
This issue has been addressed in the following products: Red Hat Enterprise Linux 5 Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 7 Via RHSA-2015:1586 https://rhn.redhat.com/errata/RHSA-2015-1586.html