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. An infinite loop flaw was found in the way the mod_dav_svn module processed certain data sets. If the SVNPathAuthz directive was set to "short_circuit", and path-based access control for files and directories was enabled, a malicious, remote user could use this flaw to cause the httpd process serving the request to consume an excessive amount of system memory. A NULL pointer dereference flaw was found in the way the mod_dav_svn module processed requests submitted against the URL of a baselined resource. A malicious, remote user could use this flaw to cause the httpd process serving the request to crash. An information disclosure flaw was found in the way the mod_dav_svn module processed certain URLs when path-based access control for files and directories was enabled. A malicious, remote user could possibly use this flaw to access certain files in a repository that would otherwise not be accessible to them. Note: This vulnerability cannot be triggered if the SVNPathAuthz directive is set to "short_circuit". Red Hat would like to thank the Apache Subversion project for reporting these issues. Upstream acknowledges Joe Schaefer of the Apache Software Foundation as the original reporter of CVE-2011-1752; Ivan Zhakov of VisualSVN as the original reporter of CVE-2011-1783; and Kamesh Jayachandran of CollabNet, Inc. as the original reporter of CVE-2011-1921. All Subversion users should upgrade to these updated packages, which contain backported patches to correct these issues. After installing the updated packages, you must restart the httpd daemon, if you are using mod_dav_svn, for the update to take effect.