Mozilla developer Ehsan Akhgari reported two issues with Cross-origin resource sharing (CORS) "preflight" requests. The first issue is that in some circumstances the same cache key can be generated for two preflight requests on a site. As a result, if a second request is made that will match the cached key generated by an earlier request, CORS checks will be bypassed because the system will see the previously cached request as applicable. In the second issue, when some Access-Control- headers are missing from CORS responses, the values from different Access-Control- headers can be used that present in the same response. External Reference: https://www.mozilla.org/en-US/security/advisories/mfsa2015-111/
Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Ehsan Akhgari as the original reporter.
This issue has been addressed in the following products: Red Hat Enterprise Linux 5 Red Hat Enterprise Linux 7 Red Hat Enterprise Linux 6 Via RHSA-2015:1834 https://rhn.redhat.com/errata/RHSA-2015-1834.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 5 Red Hat Enterprise Linux 7 Red Hat Enterprise Linux 6 Via RHSA-2015:1852 https://rhn.redhat.com/errata/RHSA-2015-1852.html