OpenSearch is open-source software suite for search, analytics, and observability applications. Prior to versions 1.3.10 and 2.7.0, 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 queries during extremely rare race conditions potentially leading to incorrect access authorization. For this issue to be triggered, two concurrent requests need to land on the same instance exactly when query cache eviction happens, once every four hours. OpenSearch 1.3.10 and 2.7.0 contain a fix for this issue.