McKesson said it was hit by a cyberattack involving third-party applications.

The Irving, Texas-based pharmaceutical distributor said Friday it's in the early stages of investigating the incident, which involved unauthorized access and exfiltration of data.

McKesson said its customers may experience some service issues that it believes could be related to the incident.

The company said its investigation remains ongoing, and it is working with cybersecurity industry experts to help with its response. The company said it has not determined that the incident is material or that it has had any material effect on the company, including its financial condition.