By late Sunday, CRA reported it had fixed its system and tested for the vulnerability, and had brought the services back online.
In an update posted on the CRA website, the agency said that as of 5 p.m. ET Sunday, individuals and businesses were able to file electronically, make payments and access all other digital services, but provided no details about what caused the temporary suspension.
Canada Revenue Agency has temporarily shut down its online services, including electronic tax filing, due to an Internet vulnerability.
The agency had shut down some services Friday at around 2 p.m. ET after discovering a potential security risk.
"We took this action as a precaution, not as the result of a successful hack or breach".
You can still complete your tax forms, but will have to wait before filing online.
The services include ones such as "My Account", "My Business Account", "Netfile", "EFILE" and "Auto-Fill My Return".
John Glowacki with Shared Services Canada says IT security officials were made aware of a bug in a computer program widely used by the federal government late Wednesday. If you question whether or not the CRA has received your return, you and the CRA have certainty on the filing of returns through a confirmation code that is issued only upon successful transmission.
"Tax returns filed have continued to be processed normally throughout the digital service interruption", Samson said.