Critical Vulnerability in Linux Package: Memory Exposure in CIFS Handling
Summary
DEBIAN-CVE-2025-38523: In the Linux kernel, the following vulnerability has been resolved: cifs: Fix the smbd_response slab to allow usercopy The handling of received data in the smbdirect client code involves using copy_to_iter() to copy data... Affects linux versions < 6.12.37-1. Fixed in 6.12.37-1. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Habilume
Habit tracker with a companion that grows with you
Complete habits, earn Lume Points, and watch your Lume grow as you stay consistent.
Background
The Linux package is a core component of the Debian operating system, providing essential functionality for managing hardware and system resources. It includes various subsystems, including the Common Internet File System (CIFS), which allows for file sharing over a network. This vulnerability specifically affects the handling of data in the smbdirect client code, which is crucial for secure and efficient data transfer.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the CIFS subsystem related to the smbd_response slab. The issue arises when using the copy_to_iter() function to copy data from the smbd_response struct's packet trailer to a buffer. If CONFIG_HARDENED_USERCOPY is enabled, this operation can lead to kernel memory exposure, resulting in a crash and potential data leakage. The vulnerability is triggered when the packet field of the smbd_response slab is not marked as permitted for usercopy, leading to a kernel bug and system instability.
How To Fix
Minimum fixed version
6.12.37-1
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
As a temporary workaround, users can disable the CONFIG_HARDENED_USERCOPY option in the kernel configuration, though this is not recommended as it may expose the system to other vulnerabilities. It is advisable to apply the patch as soon as possible.
Conclusion
The identified vulnerability in the Linux package poses significant risks to system stability and data security. It is crucial for users to update to the patched version to mitigate these risks. Utilizing tools like Vulert can help monitor and manage vulnerabilities effectively.
See every vulnerability recorded for linux →
FAQ
The vulnerability involves kernel memory exposure due to improper handling of data in the CIFS subsystem.
You can use Vulert, which monitors open-source vulnerabilities in your software. Simply upload your manifest file like package-lock.json to check for vulnerabilities.
Exploitation of this vulnerability can lead to system crashes and unauthorized access to sensitive data.
Yes, if exploited, this vulnerability could potentially lead to data leakage and loss of system integrity.
If immediate updates are not possible, consider disabling the CONFIG_HARDENED_USERCOPY option as a temporary measure, but be aware of the associated risks.
References
Related vulnerabilities
Recent vulnerabilities recorded for linux.
Habilume
Habit tracker with a companion that grows with you
Complete habits, earn Lume Points, and watch your Lume grow as you stay consistent.
