Elastic Cloud outage on 2026-08-05: Elasticsearch 9.5.0 contains a query-correctness defect

Further investigation confirmed the impact of this issue was limited to boolean queries containing a must, filter, or should clause, along with a must_not clause on unindexed fields. Such queries can return false-positives returning documents that should have been excluded and report higher document counts than expected. We have identified the root cause, a fix is in progress, and we are preparing a patch release. We will provide a further update by 10:00 UTC August 6.