A ROOT SERVER AT THE INTERNET'S CORE LOST TOUCH WITH ITS PEERS. WE STILL DON'T KNOW WHY

Summary from the TLDR InfoSec newsletter

For more than 4 days, the Cogent root name server fell out of sync with all 12 of its peers. Cogent has fixed the issue but has refused to comment on the cause of the disparity. This could have led to DNS Cache poisoning issues or issues in DNSSEC.