Mahara 17.04 before 17.04.8 and 17.10 before 17.10.5 and 18.04 before 18.04.1 can be used as medium to transmit viruses by placing infected files into a Leap2A archive and uploading that to Mahara. In contrast to other ZIP files that are uploaded, ClamAV (when activated) does not check Leap2A archives for viruses, allowing malicious files to be available for download. While files cannot be executed on Mahara itself, Mahara can be used to transfer such files to user computers.

Mahara 17.04 before 17.04.8 and 17.10 before 17.10.5 and 18.04 before 18.04.1 are vulnerable to the browser "back and refresh" attack. This allows malicious users with physical access to the web browser of a Mahara user, after they have logged in, to potentially gain access to their Mahara credentials.

Mahara 17.04 before 17.04.8 and 17.10 before 17.10.5 and 18.04 before 18.04.1 are vulnerable to mentioning the usernames that are already taken by people registered in the system rather than masking that information.