CyrusOne data breach
373,460 accounts exposed in a breach on 5 August 2026.
At a glance
373,460
Accounts exposed
5 August 2026
Date of the breach
7 October 2026
Added to the list
What happened
In August 2026, data centre operator CyrusOne was the target of a ShinyHunters "pay or leak" extortion attempt. The group subsequently published data allegedly obtained from the company, which included 373k unique email addresses across records relating to users, sales leads and CyrusOne employees. The data largely consisted of corporate contact information, including names, physical addresses, ph
What was exposed
- Email addresses. Email addresses were exposed. Expect more spam and phishing aimed at those addresses.
- Employers. Employer names were exposed. Scammers use them to pretend to be a colleague or the workplace.
- Job titles. Job titles were exposed. Scammers use them to aim a message at the right person.
- Names. Names were exposed. Scammers use real names to make a message look personal.
- Phone numbers. Phone numbers were exposed. Expect scam calls and text messages, some of them pretending to be the organisation.
- Physical addresses. Home or postal addresses were exposed. They can be used to make a scam letter or a fake identity look real.
- Support tickets. This kind of data was included in the breach. Treat it as exposed and be careful with messages that use it.
What to do now
It depends on what was exposed, so these steps follow the list above.
If your contact details were exposed
- Expect more spam, scam calls and phishing. Do not click links or open attachments in messages you did not expect.
- If a message mentions this breach, do not reply. Go to the organisation's own website or app instead of using a link in the message.
Whatever was exposed
- Check which other breaches include your own email address and phone number.
- Keep an eye on your accounts for a few months. Breached data is often used long after the breach.
- If you think someone is using your details, report it to the organisation and to your national cyber crime reporting service.
Check your own exposure
- Password leak check: find out whether a password has appeared in a breach. The password never leaves your browser.
- Free domain security scan: grade the email, DNS and website security of a domain you own.
Related breaches
Other breaches that exposed some of the same kinds of data.
Questel
In August 2026, the French intellectual property software and services company Questel was the target of a ShinyHunters "pay or leak" extortion campaign.
- Email addresses
- Employers
- Job titles
- Names
- +3 more
Read what happened
Infinite Campus
In March 2026, the student information system Infinite Campus was targeted in a ShinyHunters "pay or leak" extortion campaign.
- Email addresses
- Employers
- Job titles
- Names
- +4 more
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BCD Travel
In May 2026, the corporate travel management company BCD Travel was claimed as a victim of the ShinyHunters "pay or leak" extortion campaign.
- Email addresses
- Employers
- Job titles
- Names
- +3 more
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