CoinMarketCap data breach

Breach date: 2021-10-12. Added to this index: 2021-10-22. Accounts affected: about 3.1M. Domain: coinmarketcap.com.

What happened

During October 2021, 3.1 million email addresses with accounts on the cryptocurrency market capitalisation website CoinMarketCap were discovered being traded on hacking forums. Whilst the email addresses were found to correlate with CoinMarketCap accounts, it's unclear precisely how they were obtained. CoinMarketCap has provided the following statement on the data: "CoinMarketCap has become aware that batches of data have shown up online purporting to be a list of user accounts. While the data lists we have seen are only email addresses (no passwords), we have found a correlation with our subscriber base. We have not found any evidence of a data leak from our own servers — we are actively investigating this issue and will update our subscribers as soon as we have any new information."

Breach data sourced from Have I Been Pwned, used under CC BY 4.0. Additional breach metadata provided by XposedOrNot. DataExposed is an independent service and is not affiliated with or endorsed by either.

What was exposed

  • Email addresses: The email address you used to register or log in. It is the most common field in breaches because it doubles as your username on most sites.

What to do now

  1. Check whether your own address is in this dataset with the free email breach check.
  2. Review the accounts connected to this service and turn on two-factor authentication.
  3. Turn on two-factor authentication on your email account first, because it is the reset path for everything else.
  4. Treat calls and messages that quote real details about you as hostile until you verify them another way.

Frequently asked questions

What data was leaked in the CoinMarketCap breach?

The CoinMarketCap breach exposed Email addresses. About 3.1M accounts were affected.

Was I affected by the CoinMarketCap breach?

Run the free email breach check with the address you used on that service. It will tell you whether your address appears in this dataset.

What should I do about the CoinMarketCap breach?

Treat any message that quotes details from this breach as suspicious, turn on two-factor authentication, and consider removing your details from people-search sites if your address or phone was included.

Next steps