ModSecurity before 2.7.3 allows remote attackers to read arbitrary files, send HTTP requests to intranet servers, or cause a denial of service (CPU and memory consumption) via an XML external entity declaration in conjunction with an entity reference, aka an XML External Entity (XXE) vulnerability.
https://github.com/SpiderLabs/ModSecurity/commit/d4d80b38aa85eccb26e3c61b04d16e8ca5de76fe
https://github.com/SpiderLabs/ModSecurity/blob/master/CHANGES
https://bugzilla.redhat.com/show_bug.cgi?id=947842
http://www.securityfocus.com/bid/58810
http://www.openwall.com/lists/oss-security/2013/04/03/7
http://www.mandriva.com/security/advisories?name=MDVSA-2013:156
http://www.debian.org/security/2013/dsa-2659
http://secunia.com/advisories/52977
http://secunia.com/advisories/52847
http://lists.opensuse.org/opensuse-updates/2013-08/msg00031.html
http://lists.opensuse.org/opensuse-updates/2013-08/msg00025.html
http://lists.opensuse.org/opensuse-updates/2013-08/msg00020.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-April/102616.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-April/101911.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-April/101898.html