OpenSearch is a community-driven, open source fork of Elasticsearch and Kibana. There is an issue with the implementation of fine-grained access control rules (document-level security, field-level security and field masking) where they are not correctly applied to the indices that back data streams potentially leading to incorrect access authorization. OpenSearch 1.3.7 and 2.4.0 contain a fix for this issue. Users are advised to update. There are no known workarounds for this issue.