xsltUnparsedEntityURIFunction(xmlXPathParserContextPtr ctxt, int nargs){
    xmlXPathObjectPtr obj;
    xmlChar *str;

    if ((nargs != 1) || (ctxt->value == NULL)) {
        xsltGenericError(xsltGenericErrorContext,
		"unparsed-entity-uri() : expects one string arg\n");
	ctxt->error = XPATH_INVALID_ARITY;
	return;
    }
    obj = valuePop(ctxt);
    if (obj->type != XPATH_STRING) {
	obj = xmlXPathConvertString(obj);
    }

    str = obj->stringval;
    if (str == NULL) {
	valuePush(ctxt, xmlXPathNewString((const xmlChar *)""));
    } else {
	xmlEntityPtr entity;

	entity = xmlGetDocEntity(ctxt->context->doc, str);
	if (entity == NULL) {
	    valuePush(ctxt, xmlXPathNewString((const xmlChar *)""));
	} else {
	    if (entity->URI != NULL)
		valuePush(ctxt, xmlXPathNewString(entity->URI));
	    else
		valuePush(ctxt, xmlXPathNewString((const xmlChar *)""));
	}
    }
    xmlXPathFreeObject(obj);
}

This vulnerability category highlights issues in resource management where failures to properly release memory, file handles, or other resources can degrade system performance or enable denial-of-service conditions.