River Financial Corp

ITEM 1.05 Material Cybersecurity Incidents. On or about June 16, 2026, an unauthorized threat actor gained access to the network environment of River Financial Corporation, including River Bank & Trust (together, “River”). River identified the activity on or about June 19, 2026, and determined that ransomware had been deployed across portions of its server environment. River promptly took containment measures, including disabling affected administrative accounts and taking impacted systems offline. River, with the assistance of a third-party forensic firm, is investigating the nature and scope of the incident, including whether any personally identifiable information was subject to unauthorized access or exfiltration. That investigation is ongoing. As of the date of this filing, the full nature, scope, and impact of the incident have not yet been determined. River has not yet determined whether the incident is reasonably likely to materially impact its business or financial condition. Certain operations have been impacted, but River is working with external cybersecurity professionals to fully restore these operations. River will file an amendment to this Current Report on Form 8-K within four business days after it determines that such information is available.