Red Hat Security Advisory 2015-0166-01 – Subversion is a concurrent version control system which enables one or more users to collaborate in developing and maintaining a hierarchy of files and directories while keeping a history of all changes. The mod_dav_svn module is used with the Apache HTTP Server to allow access to Subversion repositories via HTTP. A NULL pointer dereference flaw was found in the way the mod_dav_svn module handled REPORT requests. A remote, unauthenticated attacker could use a specially crafted REPORT request to crash mod_dav_svn. A NULL pointer dereference flaw was found in the way the mod_dav_svn module handled certain requests for URIs that trigger a lookup of a virtual transaction name. A remote, unauthenticated attacker could send a request for a virtual transaction name that does not exist, causing mod_dav_svn to crash.