Use-After-Free Vulnerability in Linux Kernel's ksmbd Package
Summary
CVE-2025-37924: In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in kerberos authentication Setting sess->user = NULL was introduced to fix the dangling pointer created by ksmbd_free_user. Affects linux versions < 6.1.140-1. Fixed in 6.1.140-1. How to fix ↓
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Background
The Linux kernel is a core component of many operating systems, providing essential services for hardware and software interaction. The ksmbd module allows for SMB (Server Message Block) protocol support, enabling file sharing and printing services over a network. This vulnerability affects the kernel's handling of user sessions within ksmbd, potentially leading to security risks.
Vulnerability Detail
In the Linux kernel, a use-after-free vulnerability has been identified in the ksmbd module related to kerberos authentication. The issue arises when the session's user pointer is not properly managed, allowing another thread to access the user data after it has been freed. This can lead to undefined behavior, including potential data corruption or unauthorized access to sensitive information.
How To Fix
Minimum fixed version
6.1.140-1
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, no specific workaround has been provided for this vulnerability. It is recommended to apply the patch as soon as it becomes available to mitigate risks.
Conclusion
The identified use-after-free vulnerability in the Linux kernel's ksmbd module poses significant security risks. Users are encouraged to update their systems promptly to the patched version of the kernel to mitigate these risks. Monitoring tools like Vulert can assist in identifying vulnerabilities in your software.
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FAQ
A use-after-free vulnerability occurs when a program continues to use a memory reference after it has been freed, leading to potential security risks such as data corruption or unauthorized access.
This vulnerability can allow an attacker to exploit the ksmbd module, potentially leading to unauthorized access to user sessions and sensitive data.
If you are using a version of the Linux kernel that includes the ksmbd module, it is advisable to check for updates and apply any patches provided by your distribution.
While there are no specific workarounds available, it is crucial to monitor for updates and apply them as soon as possible to mitigate the risk.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software using just a manifest file like package-lock.json. You can check if your application is affected by this vulnerability using the Vulert playground without any signup.
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