A flaw was discovered in Elasticsearch 7.17.0’s upgrade assistant, in which upgrading from version 6.x to 7.x would disable the in-built protections on the security index, allowing authenticated users with “*” index permissions access to this index.
https://security.netapp.com/advisory/ntap-20220729-0003/
https://discuss.elastic.co/t/elastic-stack-7-17-1-security-update/298447