_zip_dirent_set_version_needed(zip_dirent_t *de, bool force_zip64) {
    zip_uint16_t length;

    if (de->comp_method == ZIP_CM_LZMA) {
	de->version_needed = 63;
	return;
    }

    if (de->comp_method == ZIP_CM_BZIP2) {
	de->version_needed = 46;
	return;
    }

    if (force_zip64 || _zip_dirent_needs_zip64(de, 0)) {
	de->version_needed = 45;
	return;
    }
    
    if (de->comp_method == ZIP_CM_DEFLATE || de->encryption_method == ZIP_EM_TRAD_PKWARE) {
	de->version_needed = 20;
	return;
    }

    /* directory */
    if ((length = _zip_string_length(de->filename)) > 0) {
	if (de->filename->raw[length-1] == '/') {
	    de->version_needed = 20;
	    return;
	}
    }
    
    de->version_needed = 10;
}

The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations.