CVE-2026-72186 ntfs: make system files immutable to prevent corruption
A local attacker can corrupt NTFS volumes and cause system deadlocks by writing to protected system files, requiring a kernel patch.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72186?
CVE-2026-72186 is a critical denial of service vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ntfs: make system files immutable to prevent corruption
When a system file such as $Bitmap is exposed via show_sys_files and written from userspace, the volume is corrupted and, because the cluster allocator scans $Bitmap through the same inode's page cache, a write to $Bitmap also deadlocks writeback against the folio it already holds locked.
These files are maintained by the driver itself and have no valid reason to be written through the file interface. Mark base metadata files (mft_no < FILE_first_user) as immutable during inode read so the VFS rejects write, mmap, truncate and unlink with -EPERM. Directories are skipped so the root and $Extend remain usable. Internal metadata updates do not go through the VFS write path and are unaffected.
Which versions are affected by CVE-2026-72186?
How do I fix CVE-2026-72186?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-72186 being exploited?
There is no known exploitation of CVE-2026-72186 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-72186, GHSA-cpf7-qp55-xqgv, UBUNTU-CVE-2026-72186.