fastjson-jsontype-rce-lab

Docker labs + defensive scanner for fastjson remote-class-load RCE. fastjson 1.2.66-1.2.83: @JSONType resource probe (CVE-2026-16723). fastjson2 2.0.57: attacker @type reaches loadClass with autoType DISABLED via polymorphic types (@JSONType(seeAlso) / Jackson @JsonSubTypes). Marker-only payloads; safeMode + JDK17 controls. Maintained by dinosn on GitHub, where it has earned 203 stars from the community.

It's actively developed around appsec, deserialization, fastjson, and is a solid reference for anyone building with these tools.