The req_check_access function in the mod_authz_svn module in the httpd server in Apache Subversion before 1.8.16 and 1.9.x before 1.9.4 allows remote authenticated users to cause a denial of service (NULL pointer dereference and crash) via a crafted header in a (1) MOVE or (2) COPY request, involving an authorization check.<a href=http://cwe.mitre.org/data/definitions/476.html>CWE-476: NULL Pointer Dereference</a> http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-2168