Monica 4.1.2 is vulnerable to Cross Site Scripting (XSS). A malicious user can create a malformed contact and use that contact in the "HOW YOU MET" customization options to trigger the XSS.
MonicaHQ v4.1.2 was discovered to contain an authenticated Client-Side Injection vulnerability via the Reason parameter at /people/h:[id]/debts/create.
MonicaHQ v4.1.2 was discovered to contain multiple Client-Side Injection vulnerabilities via the first_name and last_name parameters in the Add a new relationship feature.
MonicaHQ v4.1.2 was discovered to contain multiple authenticated Client-Side Injection vulnerabilities via the title and description parameters at /people/ID/reminders/create.