UPDATE 29-03-2024: Bug described below was addressed in 5.0.13.92028 released on 26th March. However not long since this event, a new exploit is now being used in similar manner - publishing malformed map, then hosting such map publicly, will trigger a game client crash.
This new variant is harmless - cannot be exploited to distribute malware or anything of this sort. More info about it on the SC2 Forum.
The sad part is that it requires an engine-level fix, or a server-side validation of published maps. Not something we - as a community without access to the code - can help in anyway, it's up to Blizzard now.