https://www.drupal.org/sa-core-2018-002
Might want to do some searching of your servers:
grep -m1 -r --include "CHANGELOG.txt" "^Drupal [0-9]*" /webroot or better yet find /webroot -name CHANGELOG.txt | xargs grep -m1 "^Drupal [0-9]*"
For those of you playing along at home, the exploits are published:
https://www.exploit-db.com/exploits/44448/