CVE-2026-89612 ntfs: reject invalid MFT LCNs from boot sector
A crafted NTFS image can cause an integer overflow leading to out-of-bounds memory access, potentially crashing the system.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89612?
CVE-2026-89612 is a critical vulnerability in Linux, published on 11 Sep 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: reject invalid MFT LCNs from boot sector
The NTFS boot sector stores the MFT and MFTMirr locations as unsigned 64-bit LCNs, but parse_ntfs_boot_sector() decoded them into an s64.
A crafted high-bit value could therefore become negative and pass the existing upper-bound check. The invalid value then propagated into the MFT zone allocator and could result in an out-of-bounds access to lcn_empty_bits_per_page.
Which versions are affected by CVE-2026-89612?
How do I fix CVE-2026-89612?
Apply the vendor's patch.
Is CVE-2026-89612 being exploited?
There is no known exploitation of CVE-2026-89612 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-89612, GHSA-v9qj-wpxr-47gc, UBUNTU-CVE-2026-89612.