The U.S. government has been hit in a global hacking campaign that exploited a vulnerability in widely used software but does not expect it to have significant impact, the nation’s cyber watchdog agency said on Thursday.

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) said several federal bodies had experienced intrusions following the discovery of a weakness in the file transfer software MOVEit, Eric Goldstein, the agency’s executive assistant director for cybersecurity, said in a statement.

“We are working urgently to understand impacts and ensure timely remediation,” he said. CNN first reported on the statement.

CISA did not identify the agencies that were hit or say exactly how they had been affected. It did not immediately respond to requests seeking further comment. The FBI and National Security Agency also did not immediately respond to emails seeking details on the breaches.