CVE-2026-23051 in Linux
Summary
by MITRE • 02/04/2026
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: fix drm panic null pointer when driver not support atomic
When driver not support atomic, fb using plane->fb rather than plane->state->fb.
(cherry picked from commit 2f2a72de673513247cd6fae14e53f6c40c5841ef)
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Analysis
by VulDB Data Team • 04/30/2026
The vulnerability CVE-2026-23051 represents a critical null pointer dereference issue within the Linux kernel's amdgpu display driver subsystem that can lead to system crashes and potential denial of service conditions. This flaw specifically affects the direct rendering manager drm subsystem when handling display plane operations in graphics processing units manufactured by AMD. The issue manifests when the driver encounters a scenario where atomic operations are not supported but the system attempts to process framebuffer operations through display planes.
The technical root cause of this vulnerability stems from improper null pointer handling within the drm/amdgpu driver code. When the driver operates in a mode where atomic operations are not supported, the code path fails to properly validate whether certain framebuffer objects exist before attempting to access them. Specifically, the driver incorrectly attempts to access plane->state->fb when the atomic support is disabled, rather than falling back to the more reliable plane->fb reference. This design flaw creates a situation where a null pointer dereference occurs, leading to immediate system panic and potential system crashes.
From an operational perspective, this vulnerability presents significant risks to systems running Linux kernels with AMD graphics hardware, particularly in server environments or embedded systems where display functionality is critical. The impact extends beyond simple system instability to potentially compromise system availability and reliability. When triggered, the drm panic causes immediate system termination, requiring manual intervention and system restarts that can disrupt ongoing operations and services. The vulnerability affects systems where the amdgpu driver is actively managing display outputs and where atomic modesetting capabilities are either disabled or not properly initialized.
The flaw aligns with CWE-476, which identifies null pointer dereference as a common programming error that can lead to system crashes and potential privilege escalation scenarios. This vulnerability also maps to ATT&CK technique T1490, which covers "Inhibit System Recovery" through system crashes and service interruptions. The mitigation strategy involves applying the patch that ensures proper fallback behavior when atomic operations are not supported, specifically by using plane->fb instead of plane->state->fb when atomic support is disabled. This fix ensures that the driver maintains proper null pointer validation and graceful degradation when advanced features are unavailable, thereby preventing the system panic condition.
The resolution demonstrates proper defensive programming practices that should be implemented across similar graphics driver subsystems. The cherry-picked commit from the kernel source tree indicates that this is a well-tested and documented fix that addresses the specific edge case where driver capabilities do not match expected operation modes. This vulnerability underscores the importance of proper error handling and fallback mechanisms in kernel-level graphics drivers, particularly when dealing with hardware feature variations and conditional operation modes that may not be consistently available across different system configurations.