Database
[{"_id":"uezyuLx4jjfvcqN","CVE":["CVE2020-123","CVE2022-789","CVE2019-456"],"ip":"1.2.3.4"},{"_id":"dCC8GrNdEjym3ryua","CVE":["CVE2020-123","CVE2021-469"],"ip":"5.6.7.8"},{"_id":"dCC8GrNdEjym3ryub","CVE":["CVE2020-123","CVE2021-469"],"ip":"7.6.7.6"}]
Query
db.collection.aggregate([{$match:{"ip":{$in:["1.2.3.4","5.6.7.8"]}}},{$group:{_id:"",ip:{$addToSet:"$ip"},CVE:{$addToSet:"$CVE"}}},{$project:{_id:0,ip:1,CVE:{$reduce:{input:"$CVE",initialValue:[],in:{$setUnion:["$$value","$$this"]}}}}},{$set:{sum_distinct_cve:{$size:"$CVE"}}}])