Update 5/2: CD Projekt Red has rolled out a hotfix.
Less than a week after CD Projekt Red brought official support for mods to Cyberpunk 2077, it urged players to stop using them for the time being. The publisher said it's urgently working on a fix for an exploit that affects mods and custom saves on PC. "We've been made aware of a vulnerability in external DLL files the game uses which can be used to execute code on PCs," it wrote in a tweet. "For now, please refrain from using files from unknown sources."
If you plan to use @CyberpunkGame mods/custom saves on PC, use caution. We've been made aware of a vulnerability in external DLL files the game uses which can be used to execute code on PCs. Issue will be fixed ASAP. For now, please refrain from using files from unknown sources.— CD PROJEKT RED CS (@CDPRED_Support) February 2, 2021
While mods might extend the lifespan of the game (at least until CDPR eventually adds multiplayer modes), it's best to avoid using them for now. It's not worth the risk of a hacker taking over your system. The publisher said it will roll out a fix as soon as possible.
The issue is the latest in a notoriously long line of problems that have plagued Cyberpunk 2077. Last week, CDPR issued a hotfix for a game-breaking bug that it accidentally introduced in the previous major patch. The next big update, which is said to be larger and more significant than the 1.1 patch, should arrive this month. Perhaps then CDPR can turn its full attention to the free DLC it plans to start adding early this year.