CVE-2024-26949 in Linux
Summary
by MITRE • 05/01/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu/pm: Fix NULL pointer dereference when get power limit
Because powerplay_table initialization is skipped under sriov case, We check and set default lower and upper OD value if powerplay_table is NULL.
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Analysis
by VulDB Data Team • 01/26/2026
The vulnerability identified as CVE-2024-26949 represents a critical null pointer dereference condition within the Linux kernel's amdgpu display driver subsystem. This issue specifically affects the power management functionality of AMD graphics processors, where the drm/amdgpu/powerplay subsystem fails to properly handle cases involving SR-IOV (Single Root I/O Virtualization) configurations. The flaw manifests when the powerplay_table structure, which contains essential power management parameters and limits, is not properly initialized during the power management initialization process. This initialization skip occurs exclusively under SR-IOV scenarios where virtualized graphics environments are employed, creating a path where subsequent code attempts to dereference a NULL pointer that should have been populated with default values.
The technical implementation of this vulnerability stems from inadequate null pointer validation within the power management code path. When SR-IOV is enabled, the system skips the standard powerplay_table initialization routine that would normally populate the necessary power limit parameters. However, the subsequent code does not properly validate whether the powerplay_table has been initialized before attempting to access its members. This condition creates a direct path to a null pointer dereference when the system attempts to retrieve power limits, leading to immediate system instability and potential kernel panic conditions. The vulnerability specifically impacts the get power limit functionality within the powerplay subsystem, which is essential for proper GPU power management and thermal regulation in virtualized environments.
The operational impact of CVE-2024-26949 extends beyond simple system crashes, as it affects the reliability and stability of virtualized graphics environments that depend on AMD GPU power management features. Systems utilizing SR-IOV configurations for graphics virtualization, such as cloud computing platforms, virtual desktop infrastructures, and containerized applications requiring GPU acceleration, face potential service disruption when this vulnerability is exploited. The null pointer dereference can cause complete system hangs or kernel panics, requiring manual intervention to restore system functionality. This vulnerability particularly affects enterprise environments where GPU virtualization is common, as it can lead to cascading failures in virtualized workloads that depend on consistent power management behavior. The issue is classified under CWE-476 as a NULL pointer dereference, representing a fundamental flaw in pointer validation that has been present in the kernel's power management code for several releases.
Mitigation strategies for CVE-2024-26949 should focus on implementing proper null pointer checks and ensuring default value initialization in power management code paths. The fix implemented in the kernel version addresses this by adding explicit validation to check if powerplay_table is NULL before attempting to access its members, with appropriate default values set for lower and upper OD (OverDrive) values when initialization is skipped under SR-IOV conditions. System administrators should ensure immediate patching of affected kernel versions, particularly in virtualized environments where SR-IOV is enabled. The vulnerability also highlights the importance of proper input validation and defensive programming practices in kernel space code, as recommended by the ATT&CK framework's defense evasion techniques that emphasize robust error handling. Organizations should implement monitoring for kernel panic events and system instability indicators that may signal exploitation of this vulnerability. Additionally, maintaining up-to-date kernel versions and implementing proper virtualization security configurations can help prevent exploitation of similar null pointer dereference vulnerabilities in other kernel subsystems.