Detail:
This vulnerability allows active sessions associated with an account to remain active even after enabling 2FA.

Reproduce:

• Access the same account on https://app.cal.com/ using two different devices.
• On device 'A', navigate to https://app.cal.com/settings/security/two-factor-auth and enable the 2FA system.

What should happen:
Once the 2FA system is activated, all existing active sessions should be immediately invalidated for security purposes. This then should expect the user to log in to their cal.com account again using 2FA

Current Behavior:
When activitating 2FA on your Cal.com account on Device A, Device B stays logged in without having to verify your identity.

Recommended Solution:
Upon enabling 2FA on one device, all other active sessions associated with the same account should be immediately terminated.