Ernst & Young reveals data breach following support system hack

Ernst & Young confirms breach via third-party IT service management platform, exposing clients’ tax data between March 28 and April 12, 2026
Attackers accessed documents related to tax support tickets; the exact scope and affected customers remain confidential, with no dark web leaks or group claims so far
EY has enabled incident response, secured systems and is offering 24 months of Experian identity monitoring to affected clients.

Ernst & Young (EY) has confirmed that it suffered a cyberattack in which it lost sensitive client information, including tax data.

In a data breach notification letter sent to affected individuals, the company said that on April 23, 2026, it spotted “abnormal activity” within a third-party platform used by its IT team. It is an IT service management platform that helps EY staff support teams carrying out tax-related work for clients. As a result, tickets submitted through this platform sometimes also contain documents containing customer tax information that may have been exposed during the incident.

EY then activated its incident response protocols, engaging third-party cybersecurity experts, and notifying relevant authorities and affected clients.

Free identity theft protection

Further investigation determined that the anonymous threat actors broke in on March 28, 2026 and, through April 12, exfiltrated the files. EY did not specify exactly what information had been extracted or how many clients were affected. We also don’t know if this only affects US or foreign customers. The attackers have since been removed from EY’s virtual premises and the systems have been secured, the company confirmed.

So far, no hacker group has claimed responsibility for this attack, and the data has yet to surface on the dark web. EY clients should be on the lookout for unsolicited emails, especially those claiming to come from the professional services giant.

To help them stay safe, EY offers 24 months of free identity monitoring and restoration services through Experian.

Ernst & Young is one of the four largest professional services and accounting networks in the world. Its headquarters are in London, but it operates as a global network of independent members covering more than 150 countries and employing more than 400,000 people. The Company’s core businesses include insurance, tax, advisory and M&A strategy.

Via BeepComputer