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.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Xmldom | Xmldom_project | * | 0.6.0 (including) |
| Xmldom | Xmldom_project | 0.7.0 (including) | 0.7.6 (excluding) |
| Xmldom | Xmldom_project | 0.8.0 (including) | 0.8.3 (excluding) |
| Xmldom | Xmldom_project | 0.9.0-beta1 (including) | 0.9.0-beta1 (including) |
By adding or modifying attributes of an object prototype, it is possible to create attributes that exist on every object, or replace critical attributes with malicious ones. This can be problematic if the product depends on existence or non-existence of certain attributes, or uses pre-defined attributes of object prototype (such as hasOwnProperty, toString or valueOf). This weakness is usually exploited by using a special attribute of objects called proto, constructor or prototype. Such attributes give access to the object prototype. This weakness is often found in code that assigns object attributes based on user input, or merges or clones objects recursively.