Riot Games Flags Motherboard IOMMU Flaw Enabling DMA Cheats, Urges BIOS Updates

Breaking: Riot Games Patches Hardware-Level Flaw Exploited By Cheats Across Popular Motherboards

Breaking news: Riot Games has disclosed a hardware-level security vulnerability that could let cheats bypass core anti-cheat protections in Riot titles, including Valorant and League of Legends. The flaw affects several widely used motherboard models from ASUS, Gigabyte, MSI, and ASRock.

The issue centers on the Input-Output Memory Management Unit, or IOMMU, which should shield memory from Direct Memory Access devices. In affected systems,IOMMU does not fully initialize during boot,so Pre-Boot DMA Protection may appear active in the BIOS but fail to protect the entire system.

DMA devices connect directly to PCIe and can read or write system RAM without going through the CPU or operating system. That capability can be weaponized to circumvent hardware checks that anti-cheat software relies on.

Riot Games says it quickly collaborated with motherboard manufacturers to verify the vulnerability and release BIOS updates.The goal is to close this pre-boot loophole and deter a class of cheats that previously operated with relative ease.

For players whose systems are affected, Riot will impose a temporary restriction that blocks launching Valorant until the PC is updated and security features are confirmed active.

Key Facts At A Glance

Category	Details
Affected brands	ASUS, Gigabyte, MSI, ASRock
Vulnerability	IOMMU not fully initializing at boot; DMA protection may not be active system-wide
Risk	Allows DMA devices to access memory and bypass anti-cheat checks
Remediation	Update BIOS to latest version; ensure Secure Boot, VBS, and IOMMU are enabled
Impact on players	Possible launch restrictions for Valorant until protections are verified

What Players Should Do Now

Update your motherboard BIOS to the latest version and confirm security features are active. Enable Secure Boot, Virtualization-Based Security (VBS) where available, and ensure IOMMU is turned on in BIOS settings.

After updating, restart your system and recheck security configurations. If you encounter a block from Valorant, follow Riot’s guidance to revalidate the protection status before attempting to play again.

Evergreen Insights: Why Hardware Security still Matters

Hardware-level protections like IOMMU and DMA controls are foundational to preventing low-level exploits. Even as software safeguards evolve, the integrity of memory access remains a critical battleground in competitive gaming and beyond.

For continued protection, keep firmware and drivers up to date, enable built-in security features in the BIOS, and monitor official channels for patches tied to security vulnerabilities. This incident underscores the importance of a layered approach to defense, combining hardware, firmware, and software controls.

Practical tips to strengthen your setup

• Regularly check for motherboard BIOS updates from the manufacturer and apply them promptly.
• Verify that Secure Boot, VBS, and IOMMU are enabled in BIOS/UEFI.
• Keep the operating system and anti-cheat software updated to align with firmware protections.

Engage with the Community

Have you updated your BIOS and confirmed your security features are active? Are you running a system that could be affected by IOMMU initialization issues? Share your experiences and questions in the comments below.

Has this incident changed how you think about hardware security in gaming rigs? Let us know what steps you’ve taken to safeguard your setup.

Share this breaking update with fellow players and stay tuned for follow-up guidance as more BIOS updates roll out and additional details emerge.

Disclaimer: This article provides general guidance on hardware security features. For system-specific instructions, consult your motherboard manufacturer’s documentation and official support channels.

Board that ships with IOMMU defaulting to off can be exploited.

What is the IOMMU flaw that threatens Riot Games titles?

• IOMMU (Input‑Output Memory Management Unit) is a hardware feature that isolates DMA (Direct Memory Access) transactions from devices, preventing them from reading or writing arbitrary system memory.
• A mis‑configuration on several mainstream motherboards disables or weakens IOMMU enforcement when the BIOS leaves VT‑d/AMD‑V set to “Auto” but does not enable the required IOMMU protection for PCIe devices.
• When disabled, malicious software can exploit DMA‑based cheat engines to inject code directly into the memory of Riot Games clients (e.g.,League of Legends,Valorant,Teamfight Tactics),bypassing traditional anti‑cheat detection.

How the flaw enables DMA cheats in practice

1. Cheat tool loads a vulnerable PCIe device driver (e.g., a USB‑to‑PCIe bridge or an FPGA).
2. The driver requests unrestricted DMA access; the unprotected IOMMU grants it, giving the cheat tool full read/write capability over the game process memory.
3. The cheat tampers with critical structures such as client‑side prediction, packet timestamps, and matchmaking data, allowing a user to:

• Speed‑hack or aimbot with zero latency.
• Spoof match‑making ranks.
• Extract encrypted telemetry for third‑party analysis.

Riot Games’ official response (December 2025)

• Security advisory (Riot‑SA‑2025‑12‑18): Riot publicly disclosed the vulnerability, labeling it as “critical” for all Windows‑based clients.
• Immediate actions:
• Updated the Riot Vanguard kernel driver to detect missing IOMMU protection and refuse to launch if the hardware is insecure.
• Released a patch for the game clients that adds runtime integrity checks for DMA‑related memory regions.
• Long‑term mitigation: Riot urges all players to install the latest BIOS firmware from their motherboard vendor and verify that IOMMU is actively enabled.

Which motherboards are affected?

Vendor	Typical Affected Chipsets (2023‑2025)	BIOS Flag that Disables IOMMU
ASUS	Z790, B760, X670E	IOMMU=Disabled (default on “Auto”)
MSI	Z790, B660, X670	VT‑d=Auto without “Enable IOMMU”
Gigabyte	Z690, B660, X570	Missing IOMMU=On entry in UEFI
asrock	Z790, B650, X570	AMD‑V left on “Auto” without enforcement

Note: The flaw is not limited to the models above; any board that ships with IOMMU defaulting to off can be exploited.

practical steps to secure your system

1. enter UEFI/BIOS settings (usually Delete or F2 during POST).
2. Locate the “Advanced → CPU Configuration” or “advanced → Northbridge” menu.
3. Enable one of the following options (terminology varies by vendor):

• Intel: “VT‑d” → Enabled
• AMD: “AMD‑V” or “IOMMU” → Enabled
• Save and reboot.
• Verify activation in Windows:

“`powershell

Get-WmiObject -Class Win32_DeviceMemoryAddress | Where-Object {$_.AddressSpace -eq “DMA”}

“`

– If the command returns entries,IOMMU is active.

BIOS update checklist

• Identify your exact motherboard model (e.g., ASUS ROG Strix Z790‑E Gaming).
• download the latest BIOS from the official support page (look for version 2025.12 or later).
• Create a bootable USB with the vendor’s flashing utility (e.g., ASUS EZ Flash, MSI M-Flash).
• Follow the vendor’s step‑by‑step guide to flash; do not interrupt the process.
• After flashing, repeat the IOMMU enable steps above.

Benefits of fixing the IOMMU flaw

• Enhanced game integrity – Vanguard’s anti‑cheat platform operates on a trusted hardware foundation.
• System‑wide security hardening – DMA attacks can also target password managers, encryption keys, or ransomware.
• Future‑proofing – Many upcoming titles (e.g., Valorant 2.0) will require IOMMU enforcement as a baseline security check.

Real‑world impact: riot games case study (Q4 2025)

• Incident timeline:
• Oct 2025 – Riot’s telemetry flagged an abnormal spike in “memory‑write” syscalls from a subset of Valorant clients.
• Nov 2025 – Reverse‑engineered cheat samples revealed the use of a PCIe‑based DMA injector exploiting the IOMMU mis‑config.
• Dec 2025 – Riot’s emergency patch rolled out, coupled with the public advisory.

• Outcome metrics (reported by Riot’s security team):
• Cheat detection rate rose from 68 % to 94 % after the BIOS‑update recommendation campaign.
• Player‑reported incidents dropped by 73 % within two weeks of the patch rollout.

Frequently asked questions (FAQ)

Q1: Does the flaw affect Linux or macOS players?

• The vulnerability is hardware‑based; any OS that fails to enable IOMMU can be exploited. Riot’s Linux client already enforces IOMMU at launch, while macOS’s built‑in T2 security chip mitigates DMA risks.

Q2: Will enabling IOMMU impact system performance?

• Benchmarks from TechPowerUp (Dec 2025) show a ≤ 2 % overhead on average gaming workloads,negligible for most users.

Q3: Can I use a software‑only fix?

• Riot’s client now includes a runtime IOMMU check, but without BIOS support the check will fail and the game will not start. Firmware update is mandatory.

Q4: How often should I check for BIOS updates?

• At least twice a year, or promptly after Riot publishes a security advisory referencing hardware vulnerabilities.

Fast‑reference cheat‑sheet

Action	How‑to	Why it matters
Enable IOMMU	BIOS → VT‑d / AMD‑V → Enabled	Stops unauthorized DMA
Verify IOMMU	PowerShell Get-WmiObject …	Confirms protection is active
Update BIOS	Download from vendor → flash with EZ‑Flash	Patches firmware‑level bugs
Install Riot patch	Run riot Vanguard updater	Adds runtime integrity checks
Monitor security alerts	Follow Riot Games Security Blog	Stay informed on new threats

By following these steps, gamers safeguard their League of Legends, valorant, and othre Riot titles against DMA‑based cheats while strengthening overall system security.