CVE-2026-98436 in Linux
Summary
by MITRE • 10/18/2026
In the Linux kernel, the following vulnerability has been resolved:
accel/amdxdna: Disable device buffer exporting
Device buffers are never intended to be exported. Disable exporting support explicitly.
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Analysis
by VulDB Data Team • 10/18/2026
The identified issue resides within the AMD XDNA accelerator driver in the Linux kernel, specifically concerning the handling of device buffers. In modern computing architectures involving hardware accelerators such as those found in AI or specialized processing units, memory management is a critical component that dictates how data flows between the central processing unit and the peripheral hardware. Device buffers are internal memory regions allocated by the accelerator for its own operational use, including storing intermediate results, configuration parameters, or execution contexts. These buffers are strictly intended for internal consumption by the device driver and the hardware itself, rather than for sharing with user-space applications or other kernel subsystems through export mechanisms like DMA-BUF.
The vulnerability arises from the lack of explicit restrictions on exporting these specific types of memory buffers. When a buffer is exported via standard interfaces such as dma_buf_export, it becomes accessible to external entities that may not have the necessary privileges or understanding of the internal state of the accelerator. This capability creates a potential avenue for unauthorized access or manipulation of sensitive data residing within the device's memory space. An attacker with sufficient local privileges could potentially exploit this misconfiguration to read confidential information processed by the accelerator, such as cryptographic keys or proprietary algorithmic data, leading to a breach of confidentiality. Furthermore, if an attacker can influence what is written into these buffers through exported handles, they might corrupt internal state variables, causing denial of service conditions or unexpected behavior in the acceleration tasks being performed.
From a technical perspective, this flaw represents a failure to enforce proper access controls on kernel-managed resources. It aligns with CWE-200, which classifies information exposure vulnerabilities where sensitive information is accessible to unauthorized actors. Additionally, it relates to CWE-732, as the improper assignment of permissions allows entities that should not have write or read access to interact with critical system components. In the context of the MITRE ATT&CK framework for Linux systems, this vulnerability could facilitate techniques related to Credential Access if sensitive data is exfiltrated, or Execution if corrupted buffers lead to arbitrary code execution through subsequent exploitation chains involving kernel memory corruption. The core issue is not necessarily a logic error in calculation but rather an architectural oversight where export capabilities were left enabled by default without sufficient safeguards against misuse of device-specific resources.
The operational impact of this vulnerability depends heavily on the threat model and the privileges held by potential attackers within the system environment. In multi-tenant environments or systems running untrusted workloads, the ability to access accelerator memory could lead to significant data leakage across tenant boundaries if isolation mechanisms rely partially on these buffer restrictions. Even in single-user scenarios, local privilege escalation attacks might leverage this exposure to gather information about kernel structures or other processes interacting with the same hardware device. The severity is generally considered moderate to high depending on the sensitivity of the workloads handled by the AMD XDNA accelerator and the ease with which an attacker can trigger buffer exports through available application programming interfaces exposed by the driver.
To mitigate this risk, the resolution involves explicitly disabling the export functionality for device buffers within the amdxdna driver codebase. By removing or blocking the entry points that allow these specific memory regions to be exported via dma_buf or similar mechanisms, the kernel ensures that such resources remain isolated and inaccessible to external consumers. This change enforces a principle of least privilege by ensuring that only the internal driver logic can interact with device-internal memory structures. System administrators should ensure their systems are updated with patches containing this fix as soon as they become available through official distribution channels. For environments where immediate patching is not feasible, restricting access to the accelerator devices and monitoring for unusual patterns of buffer allocation or export requests via audit logs can provide a layer of defense in depth against exploitation attempts until the software update is applied.