Err, there are such things as user level systemd unit files[0]. I have no idea if this bug gets triggered by those as well, but it's a pretty big deal if it is.

> There's a new systemd bug that gets the haters aroused!

Oiy... I feel like I am walking into the middle of a Vim/Emacs flame war. Very unfortunate.

[0] https://www.freedesktop.org/software/systemd/man/systemd.uni...

[EDIT] As noted downstream, the parsing error causes the 'User=' directive to just be ignored, so a user unit file will be run by the user. Still too many vectors of attack, sadly.