SOFA-Hessian through 4.0.2 allows remote attackers to execute arbitrary commands via a crafted serialized Hessian object because blacklisting of com.caucho.naming.QName and com.sun.org.apache.xpath.internal.objects.XString is mishandled, related to Resin Gadget. NOTE: The vendor doesn’t consider this issue a vulnerability because the blacklist is being misused. SOFA Hessian supports custom blacklist and a disclaimer was posted encouraging users to update the blacklist or to use the whitelist feature for their specific needs since the blacklist is not being actively updated

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`.