suexec in Apache HTTP Server (httpd) 2.2.3 uses a partial comparison for verifying whether the current directory is within the document root, which might allow local users to perform unauthorized operations on incorrect directories, as demonstrated using "html_backup" and "htmleditor" under an "html" directory.  NOTE: the researcher, who is reliable, claims that the vendor disputes the issue because "the attacks described rely on an insecure server configuration" in which the user "has write access to the document root."