The default installation of Apache before 1.3.19 allows remote attackers to list directories instead of the multiview index.html file via an HTTP request for a path that contains many / (slash) characters, which causes the path to be mishandled by (1) mod_negotiation, (2) mod_dir, or (3) mod_autoindex.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.