Apache Geode versions prior to 1.15.0 are vulnerable to a deserialization of untrusted data flaw when using REST API on Java 8 or Java 11. Any user wishing to protect against deserialization attacks involving REST APIs should upgrade to Apache Geode 1.15 and follow the documentation for details on enabling "validate-serializable-objects=true" and specifying any user classes that may be serialized/deserialized with "serializable-object-filter". Enabling "validate-serializable-objects" may impact performance.