Nextcloud Mail is an email application for the nextcloud personal cloud product. Affected versions shipped with a CSS minifier on the path `./vendor/cerdic/css-tidy/css_optimiser.php`. Access to the minifier is unrestricted and access may lead to Server-Side Request Forgery (SSRF). It is recommendet to upgrade to Mail 1.12.7 or Mail 1.13.6. Users unable to upgrade may manually delete the file located at `./vendor/cerdic/css-tidy/css_optimiser.php`