I've used ImgBurn regularly for over 12 years, particularly in connection with disc creation/backups for game consoles. I've used it hundreds of times.
It has not been updated since 2013.
Downloads of the final version were latterly packaged with additional but entirely optional adware/trashware (OpenCandy) but in recent years, apparently, some dodgy download sites either removed the optional choice or added other trashware.
Whatever happened that was reported to the usual places and subsequently ImgBurn itself received a bad rep rating which may result in it being flagged by anti-malware/anti-virus tools.
ImgBurn is as good as free software gets but there are plenty of other tools out there which will do an equal job:-
I've used Burnaware too, no issues with it for burning and is still being regularly updated. But it too includes an unwanted but, well flagged, optional additional program with the installer.
On a practical note I've found that for my uses it consistently refuses to verify any of the discs it has just burned. No idea why, it just reports it can not verify the disc. No problem like that with ImgBurn when used for exactly the same tasks which is one reason why I favour that instead of Burnaware.
CDBurnerXP I had no problems with either but it was sent to the naughty step too because if you did not chose the, not well highlighted, opt out download or updates you'd get unwanted, adware/trashware (Open Candy again) which would install along with program.
InfraRecorder I've used for comparative test burns only but had no trouble from it at all. A simple but functional GUI which may or may not appeal. It comes in portable versions too: 32 and 64bit with a very small footprint but no version has been updated since 2012.
I've occasionally used other burners like the obscure Padus' Discjuggler and the trial version of CloneCD for specific game console disc compatibility burning tasks. I know others interested in the same sort of things recommend the free version of Alcohol 120 and the not for free Nero.