MyRecon OSINTCyrusOne
Behind the exposed accounts
In August 2026, data centre operator CyrusOne was the target of a ShinyHunters "pay or leak" extortion attempt .
Follow the story
On 5 August 2026, CyrusOne was breached. 373,460 accounts were exposed, including email addresses, employers, job titles. MyRecon rates it 55/100, serious.
How the story unfolded
Open a step to read the detail. Missing dates stay unknown.
02Entry point
The published account does not explain the exact way the data was obtained.
03Discovery and disclosure
A separate discovery or company-disclosure date is not established by this feed record.
04Added to the breach catalogue
2026-10-07. This is the catalogue date, not necessarily the disclosure date.
05Reported outcome
373,460 accounts are listed in this breach. This is a count of accounts, not necessarily individual people. The reported exposed data includes Email addresses, Employers, Job titles, Names, Phone numbers, Physical addresses, Support tickets.
The story behind the breach
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, phone numbers and job titles.
It also included support tickets and other information related to the organisation's operations.
Breach description from Have I Been Pwned, used under a CC BY 4.0 licence.
How did it happen?
The published account does not explain the exact way the data was obtained.
What was the motive?
In August 2026, data centre operator CyrusOne was the target of a ShinyHunters "pay or leak" extortion attempt .
Reported demands or attempts to sell data describe what happened, rather than prove every attacker's intention.
What was the outcome?
373,460 accounts are listed in this breach. This is a count of accounts, not necessarily individual people.
The reported exposed data includes Email addresses, Employers, Job titles, Names, Phone numbers, Physical addresses, Support tickets.
What was exposed, and why it matters
Email addresses
The address becomes a confirmed, active target, expect more phishing, better aimed.
Employers
Connects a personal account to a workplace, which is how attackers pivot from a person to a company.
Job titles
Identifies who has access to what, which is how targets for business email compromise are picked.
Names
Turns an anonymous address into an identified person, which is what makes targeted phishing possible.
Phone numbers
Enables SIM-swap attacks against SMS two-factor codes, and puts the number on scam-call lists indefinitely.
Physical addresses
Where someone actually lives. Combined with a name this moves the risk off the internet.
Support tickets
Adds detail to a profile that can be assembled from several breaches at once.
What to do if you were in it
Questions people ask about this breach
Was my email address in the CyrusOne breach?
Use the email box on this page. The result applies only to this incident. If the provider does not cover this breach, we say so. A missing match does not prove you were unaffected.
What data was leaked in the CyrusOne breach?
email addresses, employers, job titles, names, phone numbers, physical addresses, support tickets. Each one is explained above, along with what it means for the person it belongs to.
When did it happen, and when did it become public?
The breach is dated 5 August 2026. It was published to Have I Been Pwned on 7 October 2026, a gap of 64 days during which the data was already out.
Is the CyrusOne breach real?
Yes. Have I Been Pwned lists it as verified, meaning the data was checked against the source rather than taken on trust.
How many people were affected?
373,460 accounts. That is accounts rather than people, one person often has several.
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Three kinds of content appear on this page and they are kept apart deliberately. The breach description is quoted from Have I Been Pwned under its licence. The severity score, the field-by-field explanation and the advice are computed from the record itself, every sentence derives from a number or a flag in it, which is what stops the analysis drifting from the evidence. Anything under the "MyRecon's take" byline is editorial: our reading of this breach, presented as opinion rather than as a finding.