Multiple incomplete blacklist vulnerabilities in the avatar upload functionality in manageuser.php in Collabtive before 2.1 allow remote authenticated users to execute arbitrary code by uploading a file with a (1) .php3, (2) .php4, (3) .php5, or (4) .phtml extension.
https://usn.ubuntu.com/4590-1/
https://lists.debian.org/debian-lts-announce/2020/02/msg00031.html
https://github.com/philippK-de/Collabtive/commit/9ce6301583669d0a8ecb4d23fb56e34b68511335