CVE-2026-45203 in Graphics DDK
Summary
by MITRE • 07/10/2026
Kernel software installed and running inside a Host VM may post improper commands to the GPU Firmware to trigger a memory write outside the permitted range of memory for the host kernel.
A TOCTOU bug existed where a malicious driver could modify values in memory after firmware validation but before use.
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Analysis
by VulDB Data Team • 07/10/2026
This vulnerability represents a critical kernel-level security flaw that enables unauthorized memory access through improper GPU firmware command execution within virtualized environments. The issue stems from inadequate input validation and memory boundary checking during GPU firmware interaction, allowing malicious actors to manipulate kernel memory regions beyond their intended permissions. The vulnerability manifests when kernel software executing within a host virtual machine issues malformed commands to GPU firmware components, potentially triggering memory write operations that extend beyond designated safe memory boundaries. This creates a dangerous condition where the host kernel's memory space becomes vulnerable to unauthorized modifications, potentially leading to privilege escalation and system compromise. The flaw is particularly concerning in virtualized environments where the isolation between host and guest systems depends on proper memory protection mechanisms.
The technical implementation of this vulnerability involves a time-of-check to time-of-use race condition that exists within the GPU firmware interaction logic. During the validation phase of firmware commands, legitimate values are checked and accepted, but subsequent operations occur after the validation has completed, allowing malicious drivers to modify critical memory locations between the check and actual use. This TOCTOU vulnerability creates a window where attackers can inject malicious data or alter existing values in memory before they are processed by GPU firmware components. The flaw is classified under CWE-367 which specifically addresses Time-of-Check to Time-of-Use race conditions, making it particularly dangerous as it exploits the temporal gap between validation and execution phases. Attackers can leverage this condition to manipulate kernel memory structures, potentially corrupting critical system data or injecting malicious code that persists across system operations.
The operational impact of this vulnerability extends beyond simple memory corruption, creating potential pathways for complete system compromise within virtualized environments. When a malicious driver successfully exploits this flaw, it can access and modify memory regions that should be protected from direct kernel manipulation, potentially enabling privilege escalation attacks that allow attackers to gain elevated system privileges. The vulnerability affects the fundamental security model of virtualization where host kernel memory isolation is critical for maintaining system integrity. Depending on the specific implementation and available permissions, exploitation could result in complete system takeover, data exfiltration, or persistent backdoor establishment within the host environment. The risk is amplified because the vulnerability operates at the kernel level where attackers can directly manipulate core system components without requiring user-level privileges.
Mitigation strategies for this vulnerability must address both the immediate security gap and the underlying architectural issues that enable such exploitation. System administrators should implement strict firmware validation procedures and ensure that GPU firmware commands are thoroughly validated before execution, eliminating the TOCTOU window through atomic operations or enhanced synchronization mechanisms. The recommended approach includes implementing memory access controls that prevent kernel-level memory writes outside designated boundaries, utilizing hardware memory protection features such as supervisor mode access prevention and page table permissions. Additionally, virtualization platforms should enforce stricter isolation between host and guest environments, implementing robust memory management policies that prevent unauthorized cross-boundary memory operations. Security measures should also include monitoring for suspicious GPU firmware command sequences and implementing automated detection mechanisms to identify potential exploitation attempts. Organizations must ensure firmware updates are applied promptly to address known vulnerabilities, while also conducting thorough security assessments of virtualization environments to identify similar race condition flaws within other kernel subsystems that might present comparable risks.