The U.S. Department of Homeland Security’s Computer Emergency Readiness Team (US-CERT) on Tuesday issued a security alert over a vulnerability in Symantec Corp’s antivirus software, which it referred to a “very serious event.”

The weaknesses impact 24 security products, including Symantec Endpoint Protection, Symantec Email Security, Norton Security and Symantec Protection for SharePoint Servers.

The security holes in all Symantec and Norton antivirus programs include those widely used throughout the government. Last year, Congress granted DHS new powers to scan agency networks for intruders using a federal firewall called EINSTEIN.

US-CERT recommends users and system administrators and customers fix their Symantec programs immediately by updating their anti-virus software using two patches issued by Symantec