sofa-hessian is an internal improved version of Hessian3/4 powered by Ant Group CO., Ltd. The SOFA Hessian protocol uses a blacklist mechanism to restrict deserialization of potentially dangerous classes for security protection. But there is a gadget chain that can bypass the SOFA Hessian blacklist protection mechanism, and this gadget chain only relies on JDK and does not rely on any third-party components. This issue is fixed by an update to the blacklist, users can upgrade to sofahessian version 3.5.5 to avoid this issue. Users unable to upgrade may maintain a blacklist themselves in the directory `external/serialize.blacklist`.

SOFA Hessian Remote Command Execution (RCE) Vulnerability