Critical Metadata Write Issue in Linux Kernel - CVE-2025-37931
Summary
CVE-2025-37931: In the Linux kernel, the following vulnerability has been resolved: btrfs: adjust subpage bit start based on sectorsize When running machines with 64k page size and a 16k nodesize we started seeing tree log corruption in... Affects linux versions 6.1.106-1 – 6.9.9-1. No fix is published. How to fix ↓
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Background
The Linux kernel is the core component of many operating systems, responsible for managing hardware resources and providing essential services to software applications. It is widely used in various environments, from servers to embedded systems. The kernel's stability and security are paramount, as vulnerabilities can lead to system corruption and data loss. This specific vulnerability affects the Btrfs filesystem, which is known for its advanced features like snapshots and dynamic inode allocation. The issue arises when the kernel fails to correctly manage metadata writes under certain configurations, leading to potential data corruption.
Vulnerability Detail
CVE-2025-37931 is a vulnerability in the Linux kernel's Btrfs filesystem that can cause tree log corruption due to improper handling of dirty blocks during metadata writes. The issue occurs when the system operates with a 64k page size and a 16k nodesize, combined with a 4k sectorsize. The bitmap used to track dirty ranges does not align correctly with the radix tree entries, leading to skipped writes of dirty extent buffers. This can result in significant data integrity issues, as metadata may not be written correctly, potentially corrupting the filesystem.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, users can avoid configurations that involve a 64k page size with a 16k nodesize and a 4k sectorsize. This may involve changing filesystem settings or using a different filesystem that does not exhibit this issue until a proper patch is applied.
Conclusion
CVE-2025-37931 is a critical vulnerability in the Linux kernel that affects the Btrfs filesystem, leading to potential data corruption due to improper metadata handling. Users are strongly advised to update their systems to the patched version of the Linux kernel to ensure data integrity and system stability. Temporary workarounds are available, but the best course of action is to apply the fix as soon as possible.
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FAQ
CVE-2025-37931 is a vulnerability in the Linux kernel's Btrfs filesystem that can lead to data corruption due to improper handling of metadata writes.
If your system uses the affected configurations, it may experience filesystem corruption, leading to potential data loss or instability.
You should update your Linux kernel to the patched version as soon as possible to mitigate the risk of data corruption.
Yes, you can use Vulert, which monitors open-source vulnerabilities in your software. You can check your application against this vulnerability using the Vulert playground without any signup.
Failure to address this vulnerability can result in data corruption, loss of filesystem integrity, and potential downtime for your applications.
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