CVE-2025-38319 in Linux
Summary
by MITRE • 07/10/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/pp: Fix potential NULL pointer dereference in atomctrl_initialize_mc_reg_table
The function atomctrl_initialize_mc_reg_table() and atomctrl_initialize_mc_reg_table_v2_2() does not check the return value of smu_atom_get_data_table(). If smu_atom_get_data_table() fails to retrieve vram_info, it returns NULL which is later dereferenced.
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Analysis
by VulDB Data Team • 12/19/2025
The vulnerability identified as CVE-2025-38319 represents a critical null pointer dereference flaw within the AMD display driver subsystem of the Linux kernel. This issue specifically affects the power management functionality of AMD graphics hardware through the drm/amd/pp driver component. The flaw manifests in two related functions atomctrl_initialize_mc_reg_table and atomctrl_initialize_mc_reg_table_v2_2 which are responsible for initializing memory controller register tables in the AMD GPU power management system. The vulnerability arises from inadequate error handling within the driver's initialization sequence where the return value of the smu_atom_get_data_table() function is not properly validated before subsequent memory operations.
The technical implementation of this vulnerability stems from a fundamental failure in input validation and error handling within the AMD GPU power management driver. When smu_atom_get_data_table() encounters a failure during vram_info data retrieval operations, it returns a NULL pointer to indicate the unsuccessful data acquisition. However, the calling functions atomctrl_initialize_mc_reg_table and atomctrl_initialize_mc_reg_table_v2_2 proceed to dereference this NULL pointer without prior validation, creating a condition where a null pointer dereference occurs during kernel execution. This error condition represents a classic CWE-476 Null Pointer Dereference vulnerability that can lead to kernel panics and system instability. The flaw operates at the kernel level within the display driver framework, specifically within the power management subsystem that controls GPU memory controller initialization processes.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise system stability and availability. When the null pointer dereference occurs during normal GPU power management operations, it can trigger kernel oops or panic conditions that force system reboot. This presents a significant risk in production environments where system uptime is critical, as the vulnerability can be triggered through normal GPU initialization sequences or power management transitions. The attack surface is particularly concerning as it can be exploited through legitimate GPU power management operations, making it difficult to distinguish from normal system behavior. This vulnerability directly impacts the reliability of AMD GPU systems and can lead to denial of service conditions where the graphics subsystem becomes unavailable until system reboot occurs. The flaw represents a fundamental security risk as it can potentially be leveraged to cause system instability or service disruption in environments relying on AMD graphics hardware.
Mitigation strategies for this vulnerability require immediate kernel updates from vendors providing patched versions of the Linux kernel with proper error handling implementations. System administrators should prioritize deployment of kernel versions containing the fix for this specific null pointer dereference issue, as the vulnerability exists in the core power management driver functionality. The fix involves implementing proper return value validation for smu_atom_get_data_table() calls before proceeding with memory operations, ensuring that NULL return values are handled gracefully rather than directly dereferenced. Additionally, system monitoring should be enhanced to detect kernel panic conditions related to display driver subsystem failures, as these may indicate exploitation attempts. Organizations should also implement regular kernel update policies to ensure all systems receive security patches promptly. From an operational security perspective, this vulnerability highlights the importance of robust error handling in kernel drivers and demonstrates the necessity of comprehensive testing for error conditions in system-level components. The fix aligns with ATT&CK framework techniques related to system service hardening and kernel integrity protection, emphasizing the need for proper input validation and error handling in privileged system components.