OpenProject 4.0.9 has been released with an important security bug fix and several bug fixes. We advise everyone to update their OpenProject installation.
For details on the security bug fix, please have a look at the following work package: #19243.
This error also occurred temporarily on the OpenProject demo environments. However, login information has not been affected by this error.
Thanks to L for pointing out this security error.
In the meeting plugin, a bug has been fixed which caused an internal error when the notification could not be delivered to one or several of the recipients (#19263).