Prototype Pollution in convict

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') vulnerability in Mozilla Convict.

This allows an attacker to inject attributes that are used in other components, or to override existing attributes with ones that have incompatible type, which may lead to a crash.

The main use case of Convict is for handling server-side
configurations written by the admins owning the servers, and not random
users. So it's unlikely that an admin would deliberately sabotage their
own server. Still, a situation can happen where an admin not
knowledgeable about JavaScript could be tricked by an attacker into
writing the malicious JavaScript code into some config files.

This issue affects Convict: before 6.2.4.