Need Help with MongoRuntimeError: Unexpected Null Cursor ID in Node.js (MongoDB 6.8 Issue)

Gregory_Wullimann · 2024-07-17T15:42:43.389Z

Hello everyone,

I’m encountering an issue with my Node.js application when connecting to MongoDB version 6.8. The application works fine with MongoDB 5, but when I switch to MongoDB 6.8, I get the following error:

MongoRuntimeError: Unexpected null cursor id. A cursor creating command should have set this

Here’s the context: I have an async function that connects to the MongoDB database, retrieves a collection, and iterates over its documents using a cursor. Below is a simplified version of my code:

const { MongoClient } = require('mongodb');

async function connectDB() {
    const url = "mongodb://127.0.0.1:27017/";
    console.log("Connecting to database...");

    const client = new MongoClient(url);
    await client.connect();
    console.log("Connected successfully to server");
    const dbName = "mydb";
    const db = client.db(dbName);
    const collections = await db.listCollections().toArray();
	console.log("Collections:");
	collections.forEach((collection) => {
		console.log(collection.name);
	});
    return { db, client };
}

The error happens when listing the collections. This error also happens when trying to fetch data.

Anyone can help me?

Meir_Levi · 2024-08-12T15:23:41.687Z

I also had the same issue (with 6.8.0).
I installed the 6.5.0 mongodb version and now it works for me

Ignacio_Velasco · 2025-01-20T19:55:50.567Z

Were you able to update the dependency? Im having the same error still to this day

Maverick_Pond · 2025-03-31T15:45:34.296Z

Even I’m facing the same issue after version 6.8.0. Getting error 'MongoRuntimeError: Unexpected null cursor id. A cursor creating command should have set this\n

This error is being thrown for

collection.aggregate().toArray()
collection.aggregate().next()

Can someone in the community please help us on this as we are stuck in upgrading the version since 2 weeks ?

Buddhi_Paudel · 2025-05-12T05:10:23.227Z

For people facing same issue with mongoose, I faced the similar issue with mongoose in my project.
What fixed issue with me is by adding
Making change in package.json

“@opentelemetry/instrumentation-mongodb”: “^0.53.0”,
adding overrides for mongoose
“overrides”: {
“mongoose”: {
“mongodb”: “6.5.0”
}
}

Paddy_O_Hanlon · 2025-09-03T15:15:23.142Z

I had the same issue and it turned out to be an inconsistent package-lock.json file resulting from a git merge. Deleting package-lock.json and doing npm install to create a fresh one resolved the issue.