CVE-2025-38706 in Linux
Summary
by MITRE • 09/04/2025
In the Linux kernel, the following vulnerability has been resolved:
ASoC: core: Check for rtd == NULL in snd_soc_remove_pcm_runtime()
snd_soc_remove_pcm_runtime() might be called with rtd == NULL which will leads to null pointer dereference. This was reproduced with topology loading and marking a link as ignore due to missing hardware component on the system. On module removal the soc_tplg_remove_link() would call snd_soc_remove_pcm_runtime() with rtd == NULL since the link was ignored, no runtime was created.
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Analysis
by VulDB Data Team • 02/10/2026
The vulnerability identified as CVE-2025-38706 represents a critical null pointer dereference flaw within the Linux kernel's sound subsystem, specifically in the Advanced SoC (ASoC) core component. This issue manifests during the dynamic loading and unloading of audio topology configurations where the system attempts to remove PCM runtime components. The flaw occurs when the snd_soc_remove_pcm_runtime() function receives a NULL pointer for the runtime data structure (rtd parameter), leading to an immediate system crash due to the attempted dereference of a null pointer. This type of vulnerability falls under CWE-476 which specifically addresses null pointer dereference conditions that can result in system instability and potential denial of service scenarios.
The operational impact of this vulnerability becomes particularly pronounced during audio topology loading operations when hardware components are missing from the system configuration. The issue is triggered when the system attempts to mark audio links as "ignore" due to absent hardware components, a common scenario in embedded systems where hardware variants may differ significantly. During module removal processes, the soc_tplg_remove_link() function calls snd_soc_remove_pcm_runtime() with a NULL runtime pointer because no runtime was created for the ignored link. This creates a direct path to system crash since the function does not properly validate the input parameter before attempting to access its members. The vulnerability demonstrates a classic failure in defensive programming practices where proper input validation is omitted, making it susceptible to exploitation through carefully crafted audio topology configurations.
This vulnerability directly impacts the stability and reliability of Linux-based audio systems, particularly in embedded devices, automotive infotainment systems, and other platforms where dynamic audio topology loading is utilized. The null pointer dereference can result in complete system crashes, requiring manual intervention and potentially disrupting critical audio services. From an ATT&CK framework perspective, this vulnerability could be leveraged by adversaries to perform denial of service attacks against audio services or potentially escalate privileges if the kernel's memory management is compromised during the crash handling process. The vulnerability affects systems running Linux kernel versions where the ASoC subsystem is utilized for audio processing, making it relevant across various device types including smartphones, tablets, automotive systems, and embedded multimedia platforms that rely on the Linux kernel's sound architecture.
The recommended mitigation strategies include applying the latest kernel updates that contain the patched implementation of snd_soc_remove_pcm_runtime() function with proper NULL pointer validation. System administrators should prioritize patching affected systems, particularly those running embedded audio applications or automotive infotainment systems where audio topology loading is frequently utilized. Additionally, implementing proper input validation in custom audio drivers and ensuring that topology loading processes properly handle missing hardware components can help reduce the attack surface. Monitoring for unusual audio topology loading patterns and implementing robust error handling in audio subsystems can also help detect potential exploitation attempts. Organizations should also consider implementing kernel hardening measures such as stack canaries, address space layout randomization, and other security mitigations to reduce the potential impact of similar vulnerabilities in the broader kernel sound subsystem.