CISA alerts to UEFI IOMMU initialization flaw on some motherboards

Some UEFI-supported motherboard models contain a firmware flaw that prevents proper IOMMU initialization, creating a pre-boot Direct Memory Access (DMA) vulnerability that allows a physically connected PCI Express (PCIe) device to read or modify system memory before Operating System (OS) protections are active and enabling pre-boot code injection on systems with unpatched firmware.

The advisory lists the related identifiers CVE-2025-14303, CVE-2025-11901, CVE-2025-14304, and CVE-2025‑14302 and describes UEFI implementations that report DMA protection as enabled while failing to correctly configure and activate the Input–Output Memory Management Unit (IOMMU) during the early hand-off phase of the boot sequence, permitting a DMA-capable Peripheral Component Interconnect Express (PCIe) device with physical access to perform unauthorized memory reads or writes before the OS loads.

When the IOMMU is not properly initialized, a physically present attacker using a DMA-capable PCIe device can bypass early-boot memory protections and access or alter system memory via DMA transactions processed prior to the OS enabling its security controls.

Vendors with affected products have begun issuing firmware updates that correct the IOMMU initialization sequence and restore DMA protections during early boot; because multiple vendors are involved and fixes are being published on different schedules, customers should obtain and apply published firmware packages when they become available to address the initialization failure.

The advisory’s guidance urges users and administrators to apply the latest firmware updates as soon as they are released, to monitor the Vendor Information section for newly published advisories and updated firmware packages, and to prioritize prompt patching in environments where physical access cannot be fully controlled.