Eclypsium researchers were able to find unsigned firmware in WiFi adapters, USB hubs, trackpads, and cameras that are actively used with computers from Dell, HP, Lenovo, and other major manufacturers. Attackers can use unsigned firmware to harvest and exfiltrate sensitive information, to trigger denial-of-service states, and infect them with various malware strains such as ransomware strains. Microsoft has said that the device vendor should be the one to block malicious firmware from being loaded on the device.
Source: https://www.bleepingcomputer.com/news/security/windows-linux-devices-at-risk-due-to-unsigned-peripheral-firmware/