Roundcube before 1.3.17 and 1.4.x before 1.4.12 is prone to XSS in handling an attachment’s filename extension when displaying a MIME type warning message.
bugs.debian.org/1000156
github.com/roundcube/roundcubemail/commit/7d7b1dfeff795390b69905ceb63d6391b5b0dfe7
github.com/roundcube/roundcubemail/commit/faf99bf8a2b7b7562206fa047e8de652861e624a
github.com/roundcube/roundcubemail/issues/8193
lists.debian.org/debian-lts-announce/2021/12/msg00004.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NDVGIZMQJ5IOM47Y3SAAJRN5VPANKTKO/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TP3Y5RXTUUOUODNG7HFEKWYNIPIT2NL4/
www.debian.org/security/2021/dsa-5013