CVE-2026-43127
Circular Locking Dependency in Linux Kernel NTFS3
Publication date: 2026-05-06
Last updated on: 2026-05-06
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux_kernel | ntfs3 | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a circular locking dependency in the Linux kernel's ntfs3 driver, specifically between two locks: wnd->rw_lock and ni->file.run_lock. The issue arises because one function (ntfs_extend_mft) acquires these locks in one order, while another function (run_unpack_ex) acquires them in the opposite order, creating a deadlock scenario known as AB-BA deadlock.
The deadlock happens when ntfs_extend_mft() takes ni->file.run_lock first and then wnd->rw_lock, while run_unpack_ex() takes wnd->rw_lock first and then tries to acquire ni->file.run_lock inside ntfs_refresh_zone(). This circular dependency causes the system to hang waiting for locks.
The fix involves changing run_unpack_ex() to use a non-blocking lock acquisition method (down_read_trylock()) for run_lock. If the lock is contended, the function skips ntfs_refresh_zone(), deferring the refresh to the next MFT operation, thus breaking the circular dependency and preventing the deadlock.
How can this vulnerability impact me? :
This vulnerability can cause a deadlock in the Linux kernel's ntfs3 driver, which may lead to system hangs or freezes when accessing NTFS file systems. Such deadlocks can degrade system stability and availability, potentially interrupting normal operations or causing delays in file system access.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability is fixed by updating the Linux kernel to a version where the circular locking dependency in ntfs3 has been resolved.
Specifically, the fix involves changing the locking mechanism in run_unpack_ex() to use down_read_trylock() instead of down_read(), which prevents the deadlock by skipping ntfs_refresh_zone() if the lock is contended.
Therefore, the immediate mitigation step is to apply the kernel update that includes this fix.