CIM-XML requires to apply loose validation, as stated in DSP0200:
In this discussion, any reference to well-formed or valid XML documents has the standard meaning defined in Extensible Markup Language (XML).
XML document type definitions (DTDs) are restricted to be either well-formed or valid. However, this document also uses the term loosely valid to apply to XML that removes any attributes or elements in the XML document that do not appear in the CIM XML DTD. The resulting document is valid with respect to the CIM XML DTD and is therefore loosely valid.
In effect, a loosely valid document is valid with respect to the CIM XML DTD apart from having additional attributes or elements not defined by that DTD. The concept is very similar to that of an open content model as defined by the working draft on XML Schemas, expressed within the more limited scope of DTDs. One corollary of this definition is that any XML document that is valid with respect to the CIM XML DTD is also loosely valid.