CVE-2026-93823

Received Received - Intake

Buffer Size Control Fix in Linux Kernel AMDKFD Driver

Publication date: 2026-09-24

Last updated on: 2026-10-03

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: Let driver decide buffer size at AMDKFD_IOC_GET_DMABUF_INFO ioctl amdkfd driver needs allocate buffer to return bo metadata to user space. The buffer size is controlled by user currently. It is a potential security issue that hostile value (e.g. 2 GiB) lets any render-group user trigger order-MAX allocation/OOM in kernel context. This patch first finds bo metadata size. If the size is smaller than user provided value drive can safely allocate buffer in kernel space and copy to user space buffer. If not, driver will let user know, not allocate and copy. User will redo with new buffer in user space. This patch lets driver decide buffer allocation size to avoid potential hostile size from user space. (cherry picked from commit f54ce9e8cbd3abe0eda3a285f54dc4f572fe589a)

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-24

Last Modified

2026-10-03

Generated

2026-10-15

AI Q&A

2026-09-24

EPSS Evaluated

2026-10-13

NVD

CVE-2026-93823

EUVD

EUVD-2026-86212

Affected Vendors & Products

Vendor	Product	Version / Range
amd	amdkfd	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves the AMDKFD driver's ioctl handler for AMDKFD_IOC_GET_DMABUF_INFO. The driver previously allowed user space to control the buffer size for returning buffer object metadata. A malicious user could exploit this by providing an excessively large buffer size (e.g., 2 GiB), causing the kernel to attempt an order-MAX allocation. This could lead to out-of-memory conditions or kernel crashes, as the allocation size is not validated against reasonable limits.

Detection Guidance

This vulnerability is specific to the Linux kernel's amdkfd driver and involves improper buffer size handling in the AMDKFD_IOC_GET_DMABUF_INFO ioctl. Detection requires checking kernel logs for allocation failures or OOM events related to the amdkfd driver. Commands like dmesg | grep -i amdkfd or journalctl -k | grep -i amdkfd may help identify suspicious activity.

Impact Analysis

If you are a user with access to the AMDKFD driver on a Linux system, an attacker with local access could exploit this flaw to crash the system or cause denial-of-service conditions by triggering excessive memory allocations. This could disrupt services or lead to system instability.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it is a kernel-level memory allocation issue in the AMDKFD driver. However, if exploited, it could lead to denial-of-service conditions, which may indirectly impact system availability and data processing operations subject to these regulations.

Mitigation Strategies

Update your Linux kernel to the latest patched version where this vulnerability is resolved. If an update is not immediately available, restrict access to the amdkfd driver or limit user-space processes that can interact with the AMDKFD_IOC_GET_DMABUF_INFO ioctl to reduce exposure.

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