CVE-2021-26381 in Ryzen Threadripper PRO 3000 WX-Series Processors
Summary
by MITRE • 02/10/2026
Improper system call parameter validation in the Trusted OS may allow a malicious driver to perform mapping or unmapping operations on a large number of pages, potentially resulting in kernel memory corruption.
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Analysis
by VulDB Data Team • 02/11/2026
The vulnerability identified as CVE-2021-26381 represents a critical flaw in the Trusted Operating System's kernel-level implementation that stems from inadequate validation of system call parameters. This weakness exists within the memory management subsystem where the operating system fails to properly verify the legitimacy and boundaries of memory mapping requests submitted by kernel drivers. The issue manifests when malicious or compromised drivers attempt to manipulate memory pages through mapping and unmapping operations without proper input sanitization, creating a potential pathway for unauthorized memory access patterns.
The technical root cause of this vulnerability aligns with CWE-129, which addresses improper validation of array indices and buffer boundaries. The Trusted OS kernel implementation does not adequately validate the parameters passed to system calls responsible for memory management operations such as mprotect, mmap, or similar mapping functions. When a driver submits requests for page mapping or unmapping operations, the kernel accepts these requests without sufficient validation of the page ranges, access permissions, or memory boundaries. This lack of parameter validation creates an environment where malicious drivers can submit crafted requests that exceed normal operational boundaries, potentially leading to memory corruption within kernel space.
The operational impact of CVE-2021-26381 extends beyond simple memory management issues and can result in severe system compromise. Attackers who gain the ability to manipulate kernel memory through this vulnerability could potentially execute arbitrary code with the highest privileges available to the operating system. The vulnerability creates a pathway for privilege escalation attacks where malicious drivers can manipulate kernel memory structures, potentially corrupting critical data structures or overwriting kernel code. This memory corruption could lead to system crashes, denial of service conditions, or more insidiously, provide a foothold for persistent rootkit installations that operate below the detection capabilities of standard security software.
From a threat modeling perspective, this vulnerability maps to several ATT&CK techniques including T1068, which involves exploiting legitimate credentials and system access for privilege escalation, and T1547, which covers registry run keys and startup folder modifications that could be used to establish persistence. The vulnerability's impact is particularly concerning in environments where kernel drivers are frequently loaded or where device drivers are not properly vetted for security compliance. Organizations implementing the Trusted OS platform must consider this vulnerability as a potential attack vector for sophisticated adversaries who seek to establish persistent access to sensitive systems.
Mitigation strategies for CVE-2021-26381 should focus on implementing comprehensive input validation at kernel level and strengthening the driver security model. System administrators should ensure that all kernel drivers undergo rigorous security assessment and validation before deployment, particularly those with memory management capabilities. The implementation of kernel memory protection mechanisms such as kernel address space layout randomization and stack canaries can provide additional defense in depth. Additionally, monitoring and logging of memory mapping operations should be enabled to detect anomalous patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of maintaining up-to-date kernel versions and security patches, as this issue is typically addressed through kernel updates that implement proper parameter validation and boundary checking mechanisms.