XRootD: Path traversal in directory listing allows access to the parent directory via trailing ".." pattern

The XRootD project provides a high-performance, fault-tolerant, and secure solution for handling large amounts of data distributed across multiple storage resources. Prior to version 5.9.2, XRootD's rpCheck() function in src/XrdXrootd/XrdXrootdXeq.cc rejects a parent-directory component only when two dots are followed by a slash and does not reject a terminal two-dot component. An unauthenticated attacker can append /.. to an exported path in xrdfs ls or an HTTP PROPFIND request, bypass the all.export directory scope, and cause directory and filename enumeration in the parent directory under oss.localroot. The demonstrated vector does not permit file download or disclose file contents. This issue is fixed in version 5.9.2.