Znuny before LTS 6.5.1 through 6.5.10 and 7.0.1 through 7.0.16 allows XSS. JavaScript code in the short description of the SLA field in Activity Dialogues is executed.
Znuny before LTS 6.5.1 through 6.5.10 and 7.0.1 through 7.0.16 allows DoS/ReDos via email. Parsing the content of emails where HTML code is copied from Microsoft Word could lead to high CPU usage and block the parsing process.