CVE-2026-77811 - Stored Cross-Site Scripting via Integration Template Asset in OpenSearch Dashboards

Bulletin ID: 2026-088-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 08/21/2026 13:00 PM PDT Description: Amazon OpenSearch Service is a managed service that makes it easy to deploy, operate, and scale OpenSearch clusters. We identified CVE-2026-77811, a stored cross-site scripting issue in the dashboards-observability plugin in OpenSearch Dashboards. Improper input validation in the integrations static file endpoint allows a remote authenticated actor with write permissions to OpenSearch Dashboards saved objects to upload a custom integration containing arbitrary JavaScript. When another user accesses the static file endpoint directly, the script executes in their browser session and can perform actions on their behalf, including making API calls to OpenSearch with their privileges. Affected products & versions: OpenSearch Dashboards dashboards-observability plugin (open-source, self-managed): - Affected: versions before 3.4 and versions before 2.19.6 - Fixed: versions 3.4 and 2.19.6 Amazon OpenSearch Service (AWS Managed): - Affected: versions before 3.3 - Fixed: fixed in all affected versions (via service software update) Please refer to the...