Breach date: 2026-08-21. Added to this index: 2026-09-10. Accounts affected: about 6.4M. Domain: mckesson.com.
What happened
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 data sourced from Have I Been Pwned, used under CC BY 4.0. Additional breach metadata provided by XposedOrNot. DataExposed is an independent service and is not affiliated with or endorsed by either.
What was exposed
Dates of birth: Your full birth date, day, month and year, collected at signup for age checks, identity verification, insurance quotes, birthday offers or government services.
Email addresses: The email address you used to register or log in. It is the most common field in breaches because it doubles as your username on most sites.
Employers: The name of the company or organisation you work for, collected by professional networks, job sites, insurers, lenders and many signup forms.
Genders: The gender or sex recorded on your profile, usually picked from a list at signup, sometimes with a title such as Mr or Ms or a gender identity option beyond male and female.
Names: Your first name, surname and sometimes middle name or initials, as you gave them when you signed up. It appears in almost every breach because nearly every account asks for it.
Personal health data: Information about your physical or mental health: diagnoses, medications, test results, conditions, fitness and cycle tracking, therapy notes and insurance claims, held by clinics, apps, insurers and wellness services.
Phone numbers: Your mobile or landline number, collected at signup for contact, delivery updates, marketing and two-factor codes.
Physical addresses: Your residential, postal, billing or delivery address, stored by retailers, utilities, banks, government services and almost any company that sends you something.
What to do now
Check whether your own address is in this dataset with the free email breach check.
Review the accounts connected to this service and turn on two-factor authentication.
Turn on two-factor authentication on your email account first, because it is the reset path for everything else.
Treat calls and messages that quote real details about you as hostile until you verify them another way.
Frequently asked questions
What data was leaked in the McKesson breach?
The McKesson breach exposed Dates of birth, Email addresses, Employers, Genders, Names, Personal health data, Phone numbers, Physical addresses. About 6.4M accounts were affected.
Was I affected by the McKesson breach?
Run the free email breach check with the address you used on that service. It will tell you whether your address appears in this dataset.
What should I do about the McKesson breach?
Treat any message that quotes details from this breach as suspicious, turn on two-factor authentication, and consider removing your details from people-search sites if your address or phone was included.