2026 Fiserv — Everest ransomware claim (May 29)
Data compromised
Unspecified fintech and corporate data per actor marketing
Technical writeup
BreachHistory cataloged May 29, 2026 Everest ransomware marketing against Fiserv (fiserv.com), a major U.S. financial technology and core banking processor—distinct from Fiserv’s 2023 MOVEit incident. No new Fiserv forensic bulletin matching the listing was indexed at catalog time.
Root cause
Everest extortion claim