CVE-2025-68345 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
ALSA: hda: cs35l41: Fix NULL pointer dereference in cs35l41_hda_read_acpi()
The acpi_get_first_physical_node() function can return NULL, in which case the get_device() function also returns NULL, but this value is then dereferenced without checking,so add a check to prevent a crash.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
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Analysis
by VulDB Data Team • 01/12/2026
The vulnerability identified as CVE-2025-68345 represents a critical null pointer dereference flaw within the Linux kernel's Advanced Linux Sound Architecture implementation, specifically affecting the cs35l41 hda driver component. This issue manifests in the cs35l41_hda_read_acpi() function where the acpi_get_first_physical_node() function may return a NULL value under certain conditions. The Linux Verification Center (linuxtesting.org) using SVACE tools identified this weakness during their systematic analysis of kernel components. The vulnerability resides in the handling of ACPI (Advanced Configuration and Power Interface) device node retrieval within the audio subsystem, which forms part of the broader Linux kernel's hardware abstraction layer.
The technical flaw occurs when the code path executes acpi_get_first_physical_node() which returns NULL in scenarios involving certain hardware configurations or ACPI table structures. Subsequently, the get_device() function also returns NULL since it cannot properly resolve the device reference from the null physical node. However, the code fails to implement proper null checking before attempting to dereference this NULL return value, leading to an immediate system crash. This pattern of uninitialized pointer dereference represents a classic software defect that violates fundamental safety principles in kernel development. The issue directly maps to CWE-476, which specifically addresses NULL pointer dereference vulnerabilities in software systems, and aligns with ATT&CK technique T1068 which encompasses privilege escalation through kernel-level vulnerabilities.
The operational impact of this vulnerability extends beyond simple system crashes, as it can result in complete system instability and potential denial of service conditions within audio subsystems. The cs35l41 driver is typically used for audio codec management in various laptop and desktop platforms, making this vulnerability particularly concerning for end-user systems and enterprise deployments. When triggered, the kernel panic caused by this null pointer dereference prevents normal system operation and may require manual intervention to recover. The vulnerability affects systems running Linux kernels that include the affected ALSA hda driver component, potentially impacting a wide range of computing devices including laptops, desktops, and servers that utilize this specific audio codec. The presence of this flaw in production kernel versions demonstrates the importance of comprehensive testing and validation of kernel components, particularly those handling hardware interface protocols like ACPI.
Mitigation strategies for this vulnerability should begin with immediate kernel updates from distribution vendors to incorporate the patched version of the ALSA hda driver. System administrators should prioritize patching systems running affected kernel versions, particularly in enterprise environments where audio functionality is critical. The fix implemented involves adding a simple null check before attempting to dereference the device pointer returned by get_device() function, which prevents the kernel from crashing when the ACPI physical node cannot be resolved. Additional defensive measures include monitoring system logs for kernel panic events and implementing proper system hardening practices to reduce attack surface. Organizations should also consider implementing runtime detection mechanisms to identify systems potentially vulnerable to similar null pointer dereference conditions. The vulnerability highlights the importance of comprehensive testing in kernel development environments and proper input validation for hardware interface functions, particularly when dealing with ACPI device enumeration where hardware-specific conditions can lead to unexpected null returns.