Nodebb is an open source Node.js based forum software. In affected versions a prototype pollution vulnerability in the uploader module allowed a malicious user to inject arbitrary data (i.e. javascript) into the DOM, theoretically allowing for an account takeover when used in conjunction with a path traversal vulnerability disclosed at the same time as this report. The vulnerability has been patched as of v1.18.5. Users are advised to upgrade as soon as possible.
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 |
|---|---|---|---|
| Nodebb | Nodebb | 1.15.5 (including) | 1.18.4 (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.