Hewlett Packard Enterprise discloses a material cybersecurity incident

What the filing says

On December 12, 2023, Hewlett Packard Enterprise Company (the "Company," "HPE," or "we") was notified that a suspected nation-state actor, believed to be the threat actor Midnight Blizzard, the state-sponsored actor also known as Cozy Bear, had gained unauthorized access to HPE's cloud-based email environment. The Company, with assistance from external cybersecurity experts, immediately activated our response process to investigate, contain, and remediate the incident, eradicating the activity. Based on our investigation, we now believe that the threat actor accessed and exfiltrated data beginning in May 2023 from a small percentage of HPE mailboxes belonging to individuals in our cybersecur