[15:28:23] <GothAlice> It’s called NoSQL-injection.
[15:28:47] <GothAlice> https://github.com/MongoEngine/mongoengine/issues/1991 for details and links to supporting material.
[15:30:51] <GothAlice> It can be OK if you ensure structured form deserialization isn’t a thing (e.g. POST or GET parameters of foo[]=27&foo[]=42 → Array(27, 42)) and you avoid string interpolation within $where.