A new polymorphic typing flaw was discovered in FasterXML jackson-databind, versions 2.x through 2.9.9. With default typing enabled, an attacker can send a specifically crafted JSON message to the server that allows them to read arbitrary local files.
This vulnerability relies on jdom (org.jdom) or jdom2 (org.jdom2) being present in the application's ClassPath. Applications using jackson-databind that do not also use jdom or jdom2 are not impacted by this vulnerability.