CVE-2026-72186: Linux kernel · ntfs: make system files immutable to prevent corruption
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 17 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
A fix has been implemented in the Linux kernel NTFS driver that marks critical system files as immutable, preventing unauthorized writes from userspace. Users should apply the official Linux kernel updates that include this fix. No additional mitigation is necessary as the vulnerability is addressed by this official fix.
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.
References
- nvd.nist.gov/vuln/detail/CVE-2026-72186 (opens in a new tab)
- git.kernel.org/stable/c/8f313e92522ac41d273ea137db13ea8a8df2beed (opens in a new tab)
- git.kernel.org/stable/c/f72df3a4c33b64de3418ec74d1ad4f028e09d161 (opens in a new tab)
- ubuntu.com/security/CVE-2026-72186 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72186 (opens in a new tab)
- git.kernel.org/linus/f72df3a4c33b64de3418ec74d1ad4f028e09d161 (opens in a new tab)