PHPMailer before 6.1.6 contains an output escaping bug when the name of a file attachment contains a double quote character. This can result in the file type being misinterpreted by the receiver or any mail relay processing the message.
https://usn.ubuntu.com/4505-1/
https://lists.debian.org/debian-lts-announce/2020/08/msg00004.html
https://lists.debian.org/debian-lts-announce/2020/06/msg00014.html
https://github.com/PHPMailer/PHPMailer/security/advisories/GHSA-f7hx-fqxw-rvvj
https://github.com/PHPMailer/PHPMailer/releases/tag/v6.1.6
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00085.html
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00067.html