axios before 0.33.0 (and 1.x before 1.18.0) can consume inherited properties from nested request option objects when the JavaScript process's Object.prototype has already been polluted by another com…

Summary

axios before 0.33.0 (and 1.x before 1.18.0) can consume inherited properties from nested request option objects when the JavaScript process's Object.prototype has already been polluted by another component. While the top-level merged config uses a null prototype, nested plain objects such as auth and paramsSerializer are cloned into ordinary objects and read without own-property checks. When an application passes placeholder nested objects such as auth: {} or paramsSerializer: {}, inherited use…