Critical Vulnerability in Linux Kernel: Potential Use-After-Free and Counter Refcount Underflow
Summary
DEBIAN-CVE-2024-50043: In the Linux kernel, the following vulnerability has been resolved: nfsd: fix possible badness in FREE_STATEID When multiple FREE_STATEIDs are sent for the same delegation stateid, it can lead to a possible either use-af... Affects linux versions < 6.11.4-1. Fixed in 6.11.4-1. How to fix ↓
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Background
The Linux kernel is the core component of many operating systems, providing essential services for hardware and software interaction. It is known for its stability, performance, and security features. However, like any complex software, it can have vulnerabilities. This specific issue affects the handling of state IDs in the NFS daemon, which can lead to severe security implications if exploited.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the NFS daemon (nfsd) related to the handling of FREE_STATEIDs. When multiple FREE_STATEIDs are sent for the same delegation stateid, it can result in either a use-after-free error or a counter refcount underflow. This occurs because the code drops the client lock before calling nfs4_put_stid(), allowing another FREE_STATE to access the stateid again. The first FREE_STATE then proceeds to free the stateid, leading to potential exploitation.
How To Fix
Minimum fixed version
6.11.4-1
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 highly recommended to apply the patch as soon as it is available to mitigate risks.
Conclusion
The identified vulnerability in the Linux kernel poses significant risks related to the handling of state IDs in the NFS daemon. It is essential for users to update to the patched version to protect their systems from potential exploitation. Utilizing tools like Vulert can help in monitoring and managing open-source vulnerabilities effectively.
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FAQ
The vulnerability involves potential use-after-free and counter refcount underflow errors in the NFS daemon of the Linux kernel.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software. By checking your manifest file like package-lock.json, you can identify if your application is affected.
Exploitation of this vulnerability could lead to system instability, unauthorized access, or data corruption due to improper handling of state IDs.
Yes, a patch has been released in version 6.11.4-1 of the Linux package. It is crucial to update to this version to mitigate the vulnerability.
You can use Vulert's playground to check for vulnerabilities in your application without needing to sign up. This tool provides real-time monitoring and alerts.
References
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