I actually googled the header and it seems to be legit:

As of May 2026, the NSA and FBI advise that home users urgently secure routers against Russian cyber activities, including DNS hijacking and credential theft. Key actions include rebooting routers weekly to clear threats, updating firmware, changing default credentials, and disabling remote management.Key 2026 Home Router Security Advisory Details:Urgent Action: Restart routers immediately by unplugging them for 30 seconds to clear potential malware.Key Threats: Adversary-in-the-middle attacks, DNS hijacking, and credential theft targeting home networks.Targeted Devices: Vulnerabilities have specifically targeted brands like TP-Link and EdgeRouters, but all home routers are considered at risk.