Our REI MasterCard was compromised; someone impersonating me telephoned the card issuer and attempted to change the address of record. The person had the name and card number, but did not have any other identifying information, so the issuer froze the account until they could contact me. That information would've been available from the face of the card.
I was contacted and confirmed that the call was not me, nor authorized by me. Naturally, the account has been closed and a new card is being issued with a new account number.
That's not my question.
The face of the card also shows our membership number, which presumably this party now has. Is there anything to be concerned about there? I can't see how that information could harm me, but wanted to check.