US only at the moment and reportedly to follow worldwide.
Specific models and manufacturing codes only.
News article: https://www.cyclingnews.com/news/shimano-to-recall-680000-ultegra-and-dura-ace-cranksets-due-to-crash-risk/
Shimano's own info: https://bike.shimano.com/en-US/information/customer-services/recalls-and-repairs/11-speed-HOLLOWTECH-Road-Cranksets.html
Shimano's own info on the European inspection/recall programme: https://bike.shimano.com/en-EU/information/customer-services/corrective-actions/important-safety-notice-11-speed-hollowtech-road-cranksets-inspection-program.html
Now extended to Europe as anticipated.
https://www.cyclingweekly.com/news/shimano-extends-hollowtech-crankset-inspection-programme-to-europe-amid-injury-fears