U.S. regulators told bank institutions to fix "Heartbleed," the newly discovered security hole on a widely used encryption tool. The Wall Street Journal first reported the news Thursday.
The Federal Financial Institutions Examination Council called on financial institutions to quickly patch the problem.
"FFIEC members expect financial institutions to incorporate patches on systems and services, applications, and appliances using OpenSSL and upgrade systems as soon as possible to address the vulnerability," the council said in a statement Thursday.
The Internet bug has made private data on many of the world's major websites vulnerable to theft by hackers.
Following the discovery of the breach, many Internet-users were told to change their passwords to better secure their data, but security experts told CNBC Thursday that this solution might not be enough due to the lack of traceability of the bug.
On Wednesday, the Canada Revenue Agency (CRA) said it shut down access to its online tax services due to the security flaw.