CVE-2026-72471 fs/ntfs3: prevent potential lcn remains uninitialized
An uninitialized variable in the Linux kernel NTFS3 driver can cause a kernel crash when seeking data, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72471?
CVE-2026-72471 is a high-severity vulnerability in Linux, published on 15 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: prevent potential lcn remains uninitialized
The target VCN being sought was not found within runs[0], causing run_lookup() to return false. This causes run_lookup_entry() to return false, which in turn results in a len value of 0, and the new parameter passed to attr_data_get_block() is NULL. Collectively, these factors ultimately cause attr_data_get_block_locked() to exit prematurely without initializing lcn, thereby triggering [1].
To prevent [1], the clen check within ni_seek_data_or_hole() has been moved to occur before the lcn check.
[1] BUG: KMSAN: uninit-value in ni_seek_data_or_hole+0x24f/0x5f0 fs/ntfs3/frecord.c:2862 ni_seek_data_or_hole+0x24f/0x5f0 fs/ntfs3/frecord.c:2862 ntfs_llseek+0x22a/0x4a0 fs/ntfs3/file.c:1530 vfs_llseek fs/read_write.c:391 [inline]
Which versions are affected by CVE-2026-72471?
How do I fix CVE-2026-72471?
Apply the vendor's patch.
Is CVE-2026-72471 being exploited?
There is no known exploitation of CVE-2026-72471 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-72471, GHSA-w848-j2vg-qxfr, UBUNTU-CVE-2026-72471.