bool PathExists(const FilePath& path) {
  base::ThreadRestrictions::AssertIOAllowed();
  return access(path.value().c_str(), F_OK) == 0;
}

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.