Unrestricted deserialization of untrusted data in the cursor pagination component in the OpenSearch SQL plugin allows a remote authenticated user with basic read/search permissions to execute arbitrary code on the server by sending a crafted cursor parameter to the plugins/sql endpoint.
OpenSearch SQL supports querying OpenSearch data using SQL and Piped Processing Language. In the 2.x line from 2.8.0.0 until 2.19.6.0, and the 3.x line prior to 3.7.0.0, a remote authenticated user with basic read/search permissions can provide a crafted cursor parameter to the plugins/sql endpoint and trigger unsafe deserialization of untrusted data, resulting in arbitrary code execution on the server. This issue is fixed in repository releases 2.19.6.0 and 3.7.0.0.