Critical NULL Pointer Dereference in Linux Kernel - Debian Packages
Summary
CVE-2025-21918: In the Linux kernel, the following vulnerability has been resolved: usb: typec: ucsi: Fix NULL pointer access Resources should be released only after all threads that utilize them have been destroyed. Affects linux versions < 6.1.133-1. Fixed in 6.1.133-1. How to fix ↓
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Background
The Linux kernel is the core component of the Linux operating system, responsible for managing hardware resources and providing essential services to applications. It is widely used in various distributions, including Debian 12 and 13. This vulnerability affects the USB Type-C UCSI (USB Type-C Connector System Software Interface) implementation, which is crucial for managing USB Type-C connections and devices.
Vulnerability Detail
In the Linux kernel, a NULL pointer dereference vulnerability was identified in the USB Type-C UCSI implementation. This issue arises when resources are released prematurely, leading to potential crashes or undefined behavior in the system. The vulnerability can be exploited if the associated workqueue is not completed before resource deallocation, which can compromise system stability and security.
How To Fix
Minimum fixed version
6.1.133-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade linuxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, there are no specific workarounds mentioned for this vulnerability. It is recommended to apply the patch as soon as it becomes available for Debian 12.
Conclusion
The CVE-2025-21918 vulnerability in the Linux kernel poses a significant risk due to a NULL pointer dereference in the USB Type-C UCSI implementation. Users are advised to update their systems to the patched version to mitigate potential risks. Monitoring tools like Vulert can assist in identifying vulnerabilities in your software.
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FAQ
CVE-2025-21918 is a vulnerability in the Linux kernel related to a NULL pointer dereference in the USB Type-C UCSI implementation.
Exploitation of this vulnerability can lead to system crashes or undefined behavior, potentially compromising system stability and security.
Yes, a patch is available for Debian 13 in version 6.12.19-1. Users of Debian 12 should monitor for updates.
You can use Vulert, which allows you to monitor and alert for open-source vulnerabilities in your software by analyzing your manifest file, such as package-lock.json.
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