OpenSearch Security is a plugin for OpenSearch that offers encryption, authentication and authorization. There is an observable discrepancy in the authentication response time between calls where the user provided exists and calls where it does not. This issue only affects calls using the internal basic identity provider (IdP), and not other externally configured IdPs. Patches were released in versions 1.3.9 and 2.6.0, there are no workarounds.
All versions before 1.3.9, all versions starting from 2.0.0 before 2.6.0
Unfortunately, there is no solution available yet.