EY data breach puts Big Four client-data security under scrutiny

The Economic Times reports that EY told affected clients an unauthorized third party accessed a platform used by its IT teams from March 28 to April 12, 2026, and downloaded documents concerning several clients, potentially exposing sensitive tax-service information. EY linked the wider hack to a Checkmarx software vulnerability and notified regulators in four US states. EY said its broader systems were unaffected and there was no threat to ongoing business.