Security researcher Johnathan Kuskos reported that Firefox is sending data in the body of XMLHttpRequest (XHR) HEAD requests, which goes agains the XHR specification. This can potentially be used for Cross-Site Request Forgery (CSRF) attacks against sites which do not distinguish between HEAD and POST requests. In general these flaws cannot be exploited through email in the Thunderbird and SeaMonkey products because scripting is disabled, but are potentially a risk in browser or browser-like contexts in those products. External Reference: http://www.mozilla.org/security/announce/2013/mfsa2013-54.html Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Johnathan Kuskos as the original reporter.
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 5 Via RHSA-2013:0982 https://rhn.redhat.com/errata/RHSA-2013-0982.html
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Red Hat Enterprise Linux 6 Via RHSA-2013:0981 https://rhn.redhat.com/errata/RHSA-2013-0981.html