Critical Vulnerability in Linux Kernel: UAC3 Cluster Segment Descriptor Validation Flaw
Summary
CVE-2025-39757: In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Validate UAC3 cluster segment descriptors UAC3 class segment descriptors need to be verified whether their sizes match with the declare... Affects linux versions 5.10.103-1 – 6.9.9-1. No fix is published. How to fix ↓
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Background
The Linux kernel is the core component of many operating systems, providing essential services for all other parts of the system. It manages hardware resources, facilitates communication between software and hardware, and ensures system stability. This vulnerability affects the ALSA (Advanced Linux Sound Architecture) subsystem, specifically the usb-audio driver, which handles audio devices connected via USB. The flaw arises from inadequate validation of UAC3 (USB Audio Class 3) cluster segment descriptors, potentially leading to security risks.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the ALSA usb-audio subsystem. The issue stems from the failure to validate UAC3 cluster segment descriptors properly. These descriptors must be checked to ensure their sizes align with declared lengths and fit within allocated buffer sizes. If not addressed, this flaw could allow malicious firmware to exploit the system, resulting in unexpected out-of-bounds (OOB) accesses, which could lead to system crashes or unauthorized access to sensitive data.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
Currently, no specific workarounds are provided for this vulnerability. It is recommended to apply the patches as soon as they are available to mitigate the risks associated with this flaw.
Conclusion
The vulnerability CVE-2025-39757 in the Linux kernel's ALSA usb-audio subsystem poses significant risks due to inadequate validation of UAC3 cluster segment descriptors. Users are urged to update their systems to the latest patched versions to safeguard against potential exploits. Utilizing tools like Vulert can help monitor and alert for such vulnerabilities in real-time.
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FAQ
CVE-2025-39757 is a vulnerability in the Linux kernel's ALSA usb-audio subsystem that involves inadequate validation of UAC3 cluster segment descriptors.
If exploited, this vulnerability could lead to unexpected out-of-bounds accesses, potentially causing system crashes or unauthorized access to sensitive information.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software. You can check your application against this vulnerability using the Vulert playground without any signup.
Debian 11, 12, 13, and 14 are affected, with specific patched versions available for Debian 13 (6.12.43-1) and Debian 14 (6.16.3-1).
Currently, there are no specific workarounds available. It is strongly recommended to update to the patched versions as soon as possible.
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