https://arstechnica.com/security/2024/01/new-uefi-vulnerabilities-send-firmware-devs-across-an-entire-ecosystem-scrambling/

UEFI firmware from five of the leading suppliers contains vulnerabilities that allow attackers with a toehold in a user's network to infect connected devices with malware that runs at the firmware level.

The vulnerabilities, which collectively have been dubbed PixieFail by the researchers who discovered them, pose a threat mostly to public and private data centers, and their users of course. People with even minimal access to such a network—say a paying customer, a low-level employee, or an attacker who has already gained limited entry—can exploit the vulnerabilities to infect connected devices with a malicious UEFI. Short for Unified Extensible Firmware Interface, UEFI is the low-level and complex chain of firmware responsible for booting up virtually every modern computer. By installing malicious firmware that runs prior to the loading of a main OS, UEFI infections can’t be detected or removed using standard endpoint protections. They also give unusually broad control of the infected device.