Critical Use-After-Free Vulnerability in Linux Kernel - DEBIAN-CVE-2025-21967
Summary
DEBIAN-CVE-2025-21967: In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in ksmbd_free_work_struct ->interim_entry of ksmbd_work could be deleted after oplock is freed. Affects linux versions < 6.12.20-1. Fixed in 6.12.20-1. 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 platforms, including servers, desktops, and embedded systems. The kernel's stability and security are paramount, as vulnerabilities can lead to severe system compromises.
Vulnerability Detail
In the Linux kernel, a use-after-free vulnerability has been identified in the ksmbd module, which is responsible for SMB (Server Message Block) file sharing. The vulnerability arises when the interim_entry of ksmbd_work is deleted after an oplock (opportunistic lock) is freed. This flaw can lead to unexpected behavior, including potential system crashes or unauthorized access to sensitive data, as the freed memory may still be accessed by the system.
How To Fix
Minimum fixed version
6.12.20-1
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 to mitigate potential risks.
Conclusion
The identified use-after-free vulnerability in the Linux kernel's ksmbd module poses significant risks to system security and stability. Users are urged to update to the patched version 6.12.20-1 to mitigate these risks. Regular monitoring and updates are essential for maintaining a secure environment.
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FAQ
A use-after-free vulnerability occurs when a program continues to use a memory location after it has been freed, potentially leading to arbitrary code execution or crashes.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software. By using the Vulert playground, you can check if your application is affected without requiring any installation.
The consequences may include system crashes, unauthorized access to sensitive data, or exploitation by malicious actors, which can compromise the integrity of the system.
Yes, the vulnerability affects versions prior to 6.12.20-1. It is crucial to update to this version or later to mitigate the risk.
It is advisable to regularly check for updates to your Linux kernel and other software packages to ensure that you are protected against known vulnerabilities.
References
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