The Canada Revenue Agency has temporarily cut off access to many of its electronic services.

CRA has been caught by the same security threat that is infecting hundreds of thousands of websites around the world.

A computer virus called “Heartbleed” was just discovered by security experts. They estimate it has been in operation for up to two years, allowing hackers access to supposedly-secure information such as emails and financial data.

Experts have developed a fix that will block Heartbleed. They are urging e-commerce websites to install the patch as soon as possible.

Users should check with websites before changing their passwords.

The service interruption at CRA comes as tax season heats up. As of the end of March 84% of tax returns had been filed online.