CVE-2026-18428 - OpenSearch SQL Plugin - Async Query Validation Bypass

Bulletin ID: 2026-081-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 08/13/2026 10:30 AM PDT Description: OpenSearch SQL plugin is a plugin that enables SQL and PPL query capabilities on OpenSearch clusters, including direct query integration with external data sources via Apache Spark. An issue exists where the Flint extension query handler validates SQL queries without sufficient restrictions, allowing a user with async query access to bypass the SQL grammar deny list via the direct query endpoint. Affected Products & Versions: OpenSearch SQL Plugin (open-source, self-managed): - Affected: v2.13 to v3.6 - Fixed: versions 3.7 and 2.19.6 Amazon OpenSearch Service (AWS Managed): - Affected: v2.13 to v3.5 - Fixed: v2.13 to v3.5 (via service software update) Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.