[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$f1ltse0uzqh8vi":3},{"success":4,"breach":5},true,{"_id":6,"name":7,"title":8,"slug":9,"domain":10,"breachDate":11,"addedDate":12,"publishedAt":13,"modifiedDate":14,"contentUpdatedAt":15,"source":16,"sourceUrl":17,"sourceUrls":18,"pwnCount":23,"affectedCount":23,"affectedCountStatus":24,"affectedCountLowerBound":13,"affectedCountUnit":25,"hasEnglishDescription":4,"contentLocale":26,"availableLocales":27,"translations":29,"severity":32,"dataClasses":33,"description":38,"seoTitle":39,"seoDescription":40,"logoUrl":41,"isVerified":4,"isSensitive":42,"isSpamList":42,"isMalware":42,"company":43},"6a45af988f5f5d74b4ce5f4a","MtGox","MtGox Data Breach","mtgox","mtgox.com","2011-06-01T00:00:00.000Z","2024-04-30T00:00:00.000Z",null,"2026-09-19T17:08:19.658Z","2026-07-29T11:40:53.262Z","Historical cryptocurrency exchange user database leak","https:\u002F\u002Fleakedsource.com\u002Fbreaches\u002Fmtgox-data-breach-5dddb910",[17,19,20,21,22],"https:\u002F\u002Fwww.welivesecurity.com\u002F2011\u002F06\u002F20\u002F1-bitcoin-exchange-data-breached\u002F","https:\u002F\u002Fen.bitcoin.it\u002Fwiki\u002FMt._Gox","https:\u002F\u002Fbitcointalk.org\u002Findex.php?topic=24727.0","https:\u002F\u002Fwww.justice.gov\u002Farchives\u002Fopa\u002Fpr\u002Frussian-nationals-charged-hacking-one-cryptocurrency-exchange-and-illicitly-operating-another",42163,"known","unknown","en",[26,28],"tr",{"en":30,"tr":31},{"slug":9},{"slug":9},"Medium",[34,35,36,37],"Email addresses","Usernames","Account numbers","Passwords","\u003Cp>The MtGox data breach refers to the leak of account data that occurred after unauthorized access to the user database of one of the most well-known Bitcoin exchanges at the time in June 2011. Verified records indicate that 42,163 accounts should be considered in relation to this incident. The leak centers around email addresses, usernames, account numbers, and password hashes. Although this event is often mentioned under the same heading as the cryptocurrency loss and bankruptcy process that led to the exchange's closure in 2014, this page addresses only the 2011 incident in which user account data was exposed.\u003C\u002Fp>\n\u003Ch2>Leaked Data Types and Risks\u003C\u002Fh2>\n\u003Cp>The prominent types of data in this record are email address, username, account number, and password hash. While an email address alone may seem low risk, when matched with an old exchange account, it provides a strong starting point for targeted phishing, fake refund announcements, fake support messages, and cryptocurrency-focused fraud. Usernames and account numbers allow an attacker to send messages that appear more convincing to the victim, impersonate ownership of an old exchange account, or search for the same username on other platforms. Password hashes do not mean plain text passwords; however, old and weak passwords can pose a risk, especially with hash methods that were easily cracked at the time. If the same password has been reused across different exchange, email, forum, or payment accounts, the incident can pave the way for account takeover attempts even years later.\u003C\u002Fp>\n\u003Ch2>Verified Scope and Boundaries\u003C\u002Fh2>\n\u003Cp>The verified scope is limited to account data that was exposed from the MtGox user database in 2011. The number of records is considered to be 42,163; because available breach indexes directly associate this number with the MtGox domain name and the June 2011 period. Contemporary accounts support that after accessing the database, account login information, email addresses, and encrypted passwords were spread. In contrast, this record does not represent the loss of crypto assets leading to the MtGox bankruptcy in 2014, the amounts of Bitcoin allegedly stolen from exchange wallets, or the creditor process. This distinction is important; because the user data leak is a personal account security risk, the 2014 file is a different event that must be examined separately in the context of exchange reserves and operational collapse.\u003C\u002Fp>\n\u003Ch2>User Groups at Risk\u003C\u002Fh2>\n\u003Cp>The highest risk group consists of people who opened a MtGox account during the 2011 period, used the same email address for a long time, and reused their password on other services. People who use the same nickname in cryptocurrency communities are also at additional risk, because the username can be linked to other forums, exchanges, or social accounts. Former account holders should be cautious of fake refund, creditor record, wallet verification, or support messages that appear years later. Such messages can gain trust by using the real event history and direct the user to fake login pages. Even if the email address is no longer active, accounts previously opened with the same address can become targets for identity credential attempts due to password reuse.Therefore, the risk should not be seen as limited to the MtGox account alone; all critical accounts where the same email and password history is used should be evaluated together.\u003C\u002Fp>\n\u003Ch2>Urgent Measures to Be Taken\u003C\u002Fh2>\n\u003Cp>The first step for a user with an email address in this record should be to identify all accounts where the old MtGox password or similar passwords are still being used. The priority areas for checks are the email account, crypto exchanges, financial services, password manager, cloud storage, and social media accounts. Reused passwords should be replaced with unique and long passwords. Strong second factors, such as an authentication app or hardware key, should be enabled wherever possible. The email inbox should be checked for rules, forwarding, recovery addresses, and login history; unfamiliar sessions should be closed. For messages regarding refunds, lawsuits, reimbursements, or wallet checks coming with the name MtGox, the domain should be examined carefully before clicking any links, and the requested password or recovery phrase should under no circumstances be shared.\u003C\u002Fp>\n\u003Ch2>Long-Term Security Strategies\u003C\u002Fh2>\n\u003Cp>Although this incident seems old, it carries long-term risk due to password reuse and cryptocurrency-targeted fraud. Users should use unique passwords for all critical accounts, generate strong and random values with a password manager, and treat credentials used in old exchange and forum accounts as a separate risk group. Email addresses associated with cryptocurrency assets should be segregated as much as possible; the same address should be avoided for investment, exchange, wallet, and daily communication. Account recovery options should be reviewed at regular intervals, and old phone numbers and unused email addresses should be removed. On the corporate side, employees' email addresses from past cryptocurrency exchange leaks can be considered as special scenarios in phishing training. This way, a past leak can be detected before it turns into a current access chain.\u003C\u002Fp>\n\u003Ch2>Record Control and User Action\u003C\u002Fh2>\n\u003Cp>Seeing a match in this record does not mean that the person's crypto assets have been directly stolen; the match indicates that the email or account information may be present in the 2011 user database incident. Nevertheless, the risk should be taken seriously, because when old password hashes, reused passwords, and crypto-themed phishing campaigns are considered together, the impact on account security can grow. The user should list critical accounts opened with the same email, stop password reuse, strengthen two-factor protection, and be cautious about messages using the old MtGox history. The recommended action for organizations is that when this record appears in employee emails, they should not only look at the numerical match; it is an additional control in terms of the individual's financial account access, high-privilege system roles, and password reuse risk.\u003C\u002Fp>","MtGox Data Breach (42.2 Thousand Reported Records)","MtGox Data Breach. 42.2 Thousand reported records are reported. Reported data: Email addresses, Usernames, Account numbers. Review the scope, risks, and…","\u002Fuploads\u002Flogo\u002Fmtgox.png",false,{"name":7,"sector":44,"country":45,"website":46,"websiteArchiveUrl":47,"websiteStatus":48,"websiteCheckedAt":49},"Cryptocurrency \u002F Exchange","Japan","www.mtgox.com","","reachable","2026-07-29T11:30:22.391Z"]