Kernel NULL Pointer Dereference Vulnerability in Linux Package
Summary
DEBIAN-CVE-2025-40094: In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_acm: Refactor bind path to use free() After an bind/unbind cycle, the acm->notify_req is left stale. 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 the Linux operating system, responsible for managing system resources and facilitating communication between hardware and software. It is widely used across various distributions, including Debian. This vulnerability affects the USB gadget functionality, specifically the ACM (Abstract Control Model) driver, which is used for USB communication. The vulnerability arises from improper error handling during the bind/unbind cycle, potentially leading to system instability.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the USB gadget subsystem, specifically within the f_acm driver. After a bind/unbind cycle, the notify_req pointer is left in a stale state. If a subsequent bind operation fails, the error handling mechanism attempts to free this stale request, which can result in a NULL pointer dereference when accessing the free_request function. This can lead to a kernel panic or system crash, severely impacting system reliability and security.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
Currently, there are no specific workarounds mentioned for this vulnerability. It is recommended to apply the patch as soon as it becomes available.
Conclusion
The CVE-2025-40094 vulnerability in the Linux kernel poses a significant risk due to its potential to cause system crashes through NULL pointer dereferences. Users are advised to update their systems promptly to ensure protection against this issue. Utilizing tools like Vulert can help monitor for such vulnerabilities in real-time.
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FAQ
CVE-2025-40094 is a vulnerability in the Linux kernel's USB gadget subsystem that can lead to a NULL pointer dereference, potentially causing system crashes.
This vulnerability can lead to kernel panics or crashes, affecting system stability and potentially causing data loss.
The vulnerability affects multiple Debian versions, including Debian 11, 12, 13, and 14. Users should check their kernel version and apply updates.
You can use Vulert, which monitors open-source vulnerabilities in your software. Visit Vulert Scanner to check your application without needing to sign up.
While there are no specific workarounds, it is crucial to plan for an update as soon as possible to mitigate the risk associated with this vulnerability.
References
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