bool ReplaceFile(const FilePath& from_path, const FilePath& to_path) {
  base::ThreadRestrictions::AssertIOAllowed();
  return (rename(from_path.value().c_str(), to_path.value().c_str()) == 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.