McKesson cyberattack exposes customer data and email addresses
Pharmaceutical distributor McKesson had customer data stolen in a cyberattack involving a third-party application, and also suffered service degradation. The attackers claimed to have taken 284 million records, and it was later confirmed that the stolen material included 6.4 million unique email addresses. McKesson narrowed the confirmed data theft to oncology and multispecialty customers and promised to notify patients.
Key facts
- Affected organization
- McKesson
- Incident type
- Data breach
- Occurred / detected
- Not confirmed
- Scale of damage
- Customer data including 6.4 million unique email addresses
- Cause / method
- Data theft through a cyberattack involving a third-party application
- Location
- United States
If your data was exposed
Exposed dataEmail
- Don’t tap links in texts, calls or emails that mention this incident and offer compensation, refunds or breach checks. Check directly on the organization’s official website or app.
Timeline
- McKesson disclosed a data breach, and ShinyHunters claimed to have stolen patient information.
- McKesson warned of service degradation after the cyberattack.
- McKesson confirmed that data had been stolen in a cyberattack involving a third-party application.
- A class action was filed alleging the data leak resulted from McKesson's negligence.
- It was confirmed that the stolen material included 6.4 million unique email addresses.
- McKesson narrowed the confirmed data theft to oncology and multispecialty customers and promised to notify patients.
21 related reports
- McKesson discloses breach after ShinyHunters claims patient data theft
- McKesson Corporation Data Breach Reported; Customer Data Exfiltrated
- McKesson Breach: ShinyHunters Claim 284M Records [2026]
- McKesson Confirms Data Breach as Attacker Deadline Looms
- Hackers claim millions of patient records stolen during data breach at healthcare giant McKesson
- Pharmaceutical giant McKesson warns of 'service degradation' following cyberattack
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- McKesson Hit by Cyberattack Affecting 284M Patient Records
- McKesson confirms cyber incident after ShinyHunters claims patient-data theft
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- Healthcare Giant McKesson Investigates Data Breach Incident
- McKesson Supplies 1 in 3 Hospital Prescriptions. Now It's Responding to a Cyberattack Linked to 284 Million Records
- McKesson confirms data theft in cyberattack involving third-party apps
- McKesson Data Breach: Investigation Ongoing
- McKesson Data Breach Lawsuit Investigation
- Hackers claim 284 million records in McKesson breach; physicians say misinformation is hurting care; Kennedy targets the AMA's CPT codes — Morning Medical Update Weekly Recap
- June 2026 Healthcare Data Breach Report
- McKesson Corp's negligence caused a data breach, a new class action lawsuit claims
- ShinyHunters expose 6.4M in attack on medical supplier McKesson
- McKesson Cyberattack: Stolen Data Includes 6.4 Million Unique Email Addresses
- McKesson Narrows Confirmed Data Theft from Its Cyberattack to Oncology and Multispecialty Customers, Promises Patient Notices
Other incidents at McKesson
McKesson Data Breach Exposes 284 Million Patient Records
284MImpact: 284 million patient records
A data breach occurred at McKesson, a U.S. healthcare supply chain company. The exposed data was confirmed to total 284 million patient records.
Related reports: 2 · last report →Cyberattack on McKesson
A cyberattack targeted McKesson. The attack method, the scale of the damage, the timing of the incident and the response have not been confirmed.
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The summary and key facts are written by AI from related reports and may contain errors. Check the original articles and the organization’s official statements for accurate details.