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Riot's Vanguard Now Blocks Unpatched PCs Over Motherboard IOMMU Flaw

Vendors released BIOS patches with CVE IDs after Riot uncovered a pre‑boot IOMMU initialization failure that let DMA devices access memory.

Overview

  • Players on affected Asus, Gigabyte, MSI, and ASRock boards are seeing VAN:Restriction notices and cannot launch Valorant until updated firmware is installed.
  • Riot says some firmwares reported Pre‑Boot DMA Protection as active even though the IOMMU was not fully initializing during early boot.
  • Motherboard makers have published advisories and BIOS updates, with CVE-2025-11901 (Asus), CVE-2025-14302 (Gigabyte), CVE-2025-14303 (MSI), and CVE-2025-14304 (ASRock).
  • The vulnerability enables local PCIe DMA hardware to read or write system RAM before the OS loads, allowing hardware cheats to evade detection.
  • Riot advises updating to the latest BIOS and enabling IOMMU DMA Protection (Enable with Full Protection), alongside verifying Secure Boot and VBS and avoiding untrusted PCIe devices until patched.