That said, ROMs are basically never a malware vector as they have to exploit an issue in the emulators themselves and historically that hasn't really been seen. Typically malware related to roms happens with files included in the zip archives or by sites offering "downloaders" with embedded malware.
Dolphin runs its own VM. Obviously anything is possible, but developing some kind of breakout-ROM which would infect the host machine is just way more engineering than I could imagine ever being worth it. The vector is just too complex, and the target (nerds downloading retro games) just isn't worth the squeeze.
Archive.org actually hosts a good chunk of the major Gamecube ROMs. Good luck!
For verification you generally want the Redump database, which has checksums for most disc-based console releases. Unfortunately they seem to be offline at the moment, or I'd share a canonical link. Look around for that.
DonThomasitos•1h ago