Your iCloud Keychain verification code is: $DYNAMIC_CODE

What would you like the users in this user-to-user forum to do? That looks like a short code SMS, which is at best spam and at worst an attempt to trick you into responding. See: Avoid phishing emails, fake ‘virus‘ alerts, phony support calls, and other scams

Did you receive a verification code on another device? Can you access the Keychain now?