Description
mixin-deep node module before 1.3.1 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability, which allows a malicious user to modify the prototype of "Object" via __proto__, causing the addition or modification of an existing property that will exist on all objects.
Remediation
References
https://hackerone.com/reports/311236
https://github.com/jonschlinkert/mixin-deep/commit/578b0bc5e74e14de9ef4975f504dc698796bdf9c