The electronic filing system used by U.S. federal courts has been breached in a broad cyberattack, Politico reported, citing people familiar with the incident. The intrusion is said to have compromised sensitive documents filed with district and appellate courts nationwide. Court administrators are still determining how much data was accessed or altered, and whether sealed records, grand-jury materials or national-security filings were exposed. The Administrative Office of the U.S. Courts has not yet commented publicly on the breach or on any immediate measures to contain it. The hack underscores persistent vulnerabilities in U.S. government networks and is likely to draw renewed scrutiny of the judiciary’s cybersecurity safeguards and funding. No information has been released on the suspected perpetrators or the timeline of the attack.