mongodb/node-mongodb-native · error · MongoInvalidArgumentError

Unable to continue SCRAM without valid nonce

Error message

Unable to continue SCRAM without valid nonce

What it means

Thrown by continueScramConversation() (scram.ts:127) as a MongoInvalidArgumentError when authContext.nonce is falsy at the point of computing the client proof. Like error 82, this indicates the SCRAM conversation continued without prepare() having generated and stored a nonce. An internal invariant violation, not normally user-reachable.

Source

Thrown at src/cmap/auth/scram.ts:127

  const db = credentials.source;

  const saslStartCmd = makeFirstMessage(cryptoMethod, credentials, nonce);
  const response = await connection.command(ns(`${db}.$cmd`), saslStartCmd, undefined);
  await continueScramConversation(cryptoMethod, response, authContext);
}

async function continueScramConversation(
  cryptoMethod: CryptoMethod,
  response: Document,
  authContext: AuthContext
): Promise<void> {
  const connection = authContext.connection;
  const credentials = authContext.credentials;
  if (!credentials) {
    throw new MongoMissingCredentialsError('AuthContext must provide credentials.');
  }
  if (!authContext.nonce) {
    throw new MongoInvalidArgumentError('Unable to continue SCRAM without valid nonce');
  }
  const nonce = authContext.nonce;

  const db = credentials.source;
  const username = cleanUsername(credentials.username);
  const password = credentials.password;

  const processedPassword =
    cryptoMethod === 'sha256' ? saslprep(password) : passwordDigest(username, password);

  const payload: Binary = ByteUtils.isUint8Array(response.payload)
    ? new Binary(response.payload)
    : response.payload;

  const dict = parsePayload(payload);

  const iterations = parseInt(dict.i, 10);
  if (iterations && iterations < 4096) {

View on GitHub (pinned to 3366c21a63)

Solutions

1. Ensure prepare() runs to completion before auth()/continueScramConversation()
2. Do not share a single AuthContext across concurrent connections
3. Report as a bug with the driver version if using an unmodified MongoClient

try {
  await client.connect();
} catch (e) {
  if (e instanceof MongoInvalidArgumentError && /nonce/.test(e.message)) {
    // internal invariant - file a driver bug
  }
  throw e;
}

When it happens

Trigger: continueScramConversation invoked without a preceding successful prepare(); a driver-internal state corruption where the nonce was cleared between prepare and continue; reauthenticating a pooled connection whose AuthContext was reset improperly.

Common situations: Driver defect; non-standard subclassing of ScramSHA that overrides prepare() without setting the nonce; concurrent reuse of an AuthContext across two auth attempts.

Related errors

• AuthContext must contain a valid nonce property
• Username required for mechanism '${this.mechanism}'
• AuthContext must provide credentials.
• Server returned an invalid iteration count ${iterations}
• Server returned an invalid nonce: ${rnonce}

AI-assisted analysis of mongodb/node-mongodb-native@3366c21a63 (2026-08-04). Data as JSON: /data/errors/ad53972f11229f9e.json. Report an issue: GitHub.