Code-execution flaw in UEFI firmware threatens most servers on planet Earth
Ars Technica Dan Goodin
A firmware bug could let attackers run code before Windows or Linux even starts. It hits the UEFI code most server makers and cloud providers lean on, so the blast radius is huge.
Based on reporting by Ars Technica, Dan Goodin — read the original for the full story.
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Defenders are dealing with another serious code-execution flaw, and this one sits lower than the operating system. It lives in TianoCore EDK II, the open source firmware codebase that hardware makers and cloud providers use to build UEFI, the software layer that runs during boot. Ars Technica says the flaw carries a 9.5 out of 10 severity rating, and that the code is used broadly across the server world.
That matters because EDK2 is not some niche project on the side. The UEFI Forum called it the “preeminent solution / implementation of the UEFI specifications” last year, and the reference code is used heavily by suppliers such as AMI, Insyde, and Phoenix. Microsoft’s hardened Project Mu fork also used the vulnerable component.
The bug is tracked as CVE-2026-97631. It is a memory-corruption issue in an ICMP component, which means an attacker can use it to run malicious code before the operating system has a chance to load its own defenses. That is the uncomfortable part: the code runs before protections like Secure Boot can establish a chain of trust for the rest of the boot process, including the Trusted Platform Module.
The payload from this flaw does not stick around on its own. It runs once. But once code execution happens that early, an attacker has a window to drop something else that can come back every time the machine boots. And on servers, that is not a small problem; that is the kind of problem that keeps defenders awake.
My take — AI-written commentary, not fact-checked reporting
UEFI keeps proving that the boot chain is where modern security still goes to look silly. Open source firmware is doing a lot of heavy lifting here, which is fine until one memory bug hands attackers the keys before the OS even wakes up. The industry loves talking about trust chains and hardened forks; the bug reports keep reminding everyone that firmware is where the real mess starts.
Read more about this at: Ars Technica