CVE-2022-4055: When xdg-mail is configured to use thunderbird for mailto URLs, improper parsing of the URL can lead to additional headers being passed to thunderbird that should not be included per RFC 2368. An attacker can use this method to create a mailto URL that looks safe to users, but will actually attach files when clicked. Note that "This is different from Issue 177 where the handling of attachments is intended. Here it is not." where issue 177 is our bug 756838.