MyRecon OSINT
McKesson
On 21 August 2026, McKesson was breached. 6,404,340 accounts were exposed, including dates of birth, email addresses, employers. MyRecon rates it 73/100, severe. That is about 24% of the population of Australia.
Read the data classes rather than the headline. "Personal health data" sitting next to names, dates of birth, employers and addresses is the combination that makes a breach at a distributor behave like a breach at a hospital, and McKesson is a wholesaler, not a care provider. Most of the people in this file have never knowingly had a relationship with it.
That is the pattern worth internalising about healthcare supply chains. The companies holding your health data are rarely the ones you chose: they are the clearing houses, distributors, benefit administrators and billing intermediaries that sit behind the clinic. You cannot audit them, opt out of them, or in most cases name them.
The practical consequence is narrow and specific. Health-adjacent detail is what makes a fraudulent call convincing, a caller who knows your employer, your date of birth and something about your medication has not proved they are your pharmacy. Treat any unexpected contact referencing your care as unverified, and go back through a number you already had.
The story behind the breach
In August 2026, healthcare and pharmaceutical company McKesson was targeted in a ShinyHunters "pay or leak" extortion campaign . The group subsequently published a substantial corpus of data they alleged was sourced from the company, which included 6.4M unique email addresses among other personal and corporate data attributes. The impacted data related to a range of individuals and roles, including marketing campaign recipients, patients, staff and healthcare provider contacts.
In McKesson's disclosure notice , the company advised it had identified unauthorised access to "certain third-party applications and the exfiltration of certain data was associated with a subset of customers within our Oncology & Multispecialty and Medical-Surgical business units", but had "reasonable assurance of no ongoing unauthorized activity".
Breach description from Have I Been Pwned, used under a CC BY 4.0 licence.
Read the original disclosure ↗
How did it happen?
In McKesson's disclosure notice , the company advised it had identified unauthorised access to "certain third-party applications and the exfiltration of certain data was associated with a subset of customers within our Oncology & Multispecialty and Medical-Surgical business units", but had "reasonable assurance of no ongoing unauthorized activity".
What was the motive?
In August 2026, healthcare and pharmaceutical company McKesson was targeted in a ShinyHunters "pay or leak" extortion campaign .
Reported demands or attempts to sell data describe what happened, rather than prove every attacker's intention.
What was the outcome?
6,404,340 accounts are listed in this breach. This is a count of accounts, not necessarily individual people.
The reported exposed data includes Dates of birth, Email addresses, Employers, Genders, Names, Personal health data, Phone numbers, Physical addresses.
What was exposed, and why it matters
- Dates of birthOne of the three things call centres ask to verify identity, and it never changes.
- Email addressesThe address becomes a confirmed, active target, expect more phishing, better aimed.
- EmployersConnects a personal account to a workplace, which is how attackers pivot from a person to a company.
- GendersSmall on its own; useful to anyone assembling a fuller profile.
- NamesTurns an anonymous address into an identified person, which is what makes targeted phishing possible.
- Personal health dataAdds detail to a profile that can be assembled from several breaches at once.
- Phone numbersEnables SIM-swap attacks against SMS two-factor codes, and puts the number on scam-call lists indefinitely.
- Physical addressesWhere someone actually lives. Combined with a name this moves the risk off the internet.
What to do if you were in it
- Move two-factor authentication off SMS and onto an authenticator app, which a SIM swap cannot intercept.
- Be sceptical of post and callers who already know your address, knowing it is no longer evidence of anything.
- Expect better-aimed phishing. A message that already knows your name and where you have an account is the whole point of a breach like this.
Questions people ask about this breach
Was my email address in the McKesson 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 McKesson breach?
dates of birth, email addresses, employers, genders, names, personal health data, phone numbers, physical addresses. 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 21 August 2026. It was published to Have I Been Pwned on 10 September 2026, a gap of 20 days during which the data was already out.
Is the McKesson 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?
6,404,340 accounts. That is about 24% of the population of Australia. 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.