A prototype pollution vulnerability exists in the function copy in dom.js in the xmldom (published as @xmldom/xmldom) package before 0.8.3 for Node.js via the p variable. NOTE: the vendor states "we are in the process of marking this report as invalid"; however, some third parties takes the position that "A prototype injection/Prototype pollution is not just when global objects are polluted with recursive merge or deep cloning but also when a target object is polluted."
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.