Celsius Admits Customer Emails Leaked In Third-Party Data Breach

Customers are ticked off by another snag with bankrupt crypto lender Celsius


Blockworks exclusive art by axel rangel


key takeaways

  • The same data breach that affected OpenSea has affected Celsius
  • Customer.io removed its employee responsible for email leaks

Celsius users — look out for phishing attacks. 

The cryptocurrency lender has warned customers that a data breach led to their emails being leaked.

Late Thursday, Celsius emailed users informing them that an employee at its email delivery vendor Customer.io accessed a list of client addresses and sent them to an unauthorized party.

The embattled firm said it didn’t consider the incident to pose “high risks,” and had been informed that no other Celsius-related data was compromised beyond identified email addresses. 

Loading Tweet..

About a month ago, collectibles platform OpenSea warned users that their email addresses were compromised in a similar leak. Customer.io was responsible for that incident too, since one of its employees abused their access. The vendor said that the employee responsible had been terminated, had all access removed and was reported to law enforcement.

Celsius, aware that Customer.io was one of its vendors, said it proceeded to remove data held with the firm after the OpenSea episode. At the time, the vendor found no Celsius data involved in the breach. 

But on July 8, Celsius was notified that it too had been affected by the same offender. In a statement, Customer.io confirmed five clients apart from OpenSea were impacted by the email leaks. “We do not expect to learn any additional information since this incident resulted from the actions of a single employee, who had legitimate access to these email addresses as part of the employee’s job,” it added.

Celsius customers took to Twitter to express frustration over a stream of trouble they’ve had to face with the lender. 

Loading Tweet..

The firm is dealing with restructuring its assets after filing for bankruptcy on July 13. A court document shows Celsius has $5.5 billion in liabilities and $4.3 billion in assets, leaving it with a $1.2 billion hole on its balance sheet.

And while Celsius has been quick to downplay the risk to its users, similar data breaches have shown that affected users have actually lost funds due to phishing attacks. 

When hardware wallet manufacturer Ledger suffered a data leak of its marketing database in July 2020, its users were targeted with devious scams designed to steal their cryptocurrencies.

Shopify, the e-commerce giant that Ledger used to sell its wallets, also came under attack from users for “repeatedly and profoundly” failing to protect customer identities. Both firms were sued in April after victims lost some of their crypto assets.

Start your day with top crypto insights from David Canellis and Katherine Ross. Subscribe to the Empire newsletter.


Upcoming Events

Salt Lake City, UT

WED - FRI, OCTOBER 9 - 11, 2024

Pack your bags, anon — we’re heading west! Join us in the beautiful Salt Lake City for the third installment of Permissionless. Come for the alpha, stay for the fresh air. Permissionless III promises unforgettable panels, killer networking opportunities, and mountains […]

recent research



Data publishing costs have historically been a bottleneck for rollups, and as more rollups launch, interoperability will continue to be a major challenge. Avail presents a potential solution to rollup fragmentation through its three products: Avail DA, Nexus, and Fusion, which together aim to unify the web3 experience.


Bitcoin miners need to explore unconventional energy avenues or be buried by the financial realities created by this halving


BlackRock’s iShares Bitcoin Trust continues to see daily positive net flows, though its inflow total for a single day hit a new low Wednesday


Binance is making moves, from receiving a new license in Dubai to switching its SAFU fund to USDC


Miner stocks have historically underperformed bitcoin before the halving and outperformed the asset after the event, analysts note


After a one-week trial, a jury convicted crypto trader Avraham Eisenberg


A verdict in Avraham Eisenberg’s criminal fraud trial is expected this afternoon