Apache Struts: Shared serialization state in the JSON plugin

Exposure of data element to wrong session vulnerability in the JSON plugin of Apache Struts. Per-response serialization state could be shared across concurrent requests, allowing response content associated with one request to become observable in another. Only the SMD / JSON-RPC handling of the JSON interceptor is affected, which is not enabled by default; applications using the json result type are not affected. This issue affects Apache Struts: 7.2.1. Users are recommended to upgrade to version 7.3.0, which fixes the issue.