The US federal government officially shut down on October 1 at 12:01 AM ET. Essential services related to national security, such as law enforcement, medical care, air traffic control, and disaster aid, continue to operate during a government shutdown. However, even these essential services may face disruptions. During a shutdown, some agencies furlough non-essential employees, meaning they do not work or receive pay, while essential employees are required to work without pay. Congress typically approves retroactive pay for these employees once the government reopens, but the impact on federal workers and their families is significant. One agency affected by the shutdown is CISA, the Cybersecurity and Infrastructure Security Agency under the Department of Homeland Security (DHS). CISA is responsible for protecting critical infrastructure from cyber and physical threats, including power grids, transportation systems, financial systems, healthcare, and elections. As of May 31, 2025, CISA had 2,540 employees. However, only 889 of these employees are estimated to remain working during the shutdown, which amounts to just 35% of CISA's workforce. Additionally, the Cybersecurity Information Sharing Act of 2015, which provided legal cover for companies to share hacking threats with the government and each other, expired at the end of September. The expiration of this law has left companies unsure about sharing intelligence with CISA, as they may no longer be protected from legal repercussions. Lawmakers and the White House intended to extend the law, but the budget bill that included this provision collapsed, leaving companies vulnerable to potential lawsuits. Without the legal protections provided by the Cybersecurity Information Sharing Act of 2015, companies are hesitant to share information with CISA, which weakens domestic cybersecurity efforts. This lapse in cooperation could have serious implications for the security of US networks and businesses, particularly in the face of ongoing cyber threats from private hackers and foreign governments. It is crucial for CISA to operate at full capacity and for private companies to have legal protections in place to ensure the cybersecurity of the United States during this challenging time.