Medical device maker Boston Scientific is being hit by a cyberattack. The shares are falling

Boston Scientific said Wednesday it was hit with a cyberattack this week that is affecting its operations. The disclosure sent shares of the $72 billion medical device maker lower.

The attack is disrupting Boston Scientific's access to company information systems and applications, including shipments services, the company said in a SEC filing.

"While the company is working diligently to restore affected functions and systems access, the timeline for a full restoration is not yet known," the filing said.

Shares were down 5.8% in premarket trading on Wednesday. Shares of the maker of devices such as pacemakers and stents have been nearly cut in half already this year, under pressure after issuing a weak profit forecast in the first quarter.

When asked to comment, the company reiterated the info from the SEC filing.