CVE-2026-90200

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: fix integer overflow in MFT cluster validation

In ntfs_init_from_boot(), the boot sector's MFT cluster numbers are

validated against the volume size with:

if (mlcn * sct_per_clst >= sectors ||

mlcn2 * sct_per_clst >= sectors)

goto out;

mlcn and mlcn2 are u64 fields read directly from the boot sector.

sct_per_clst is bounded above by 4096 (true_sectors_per_clst() plus

the is_power_of_2() check below it), but the multiplication is done

in u64 and wraps when mlcn (or mlcn2) is large enough -- e.g. mlcn

near 2^62 with sct_per_clst == 4 wraps to 0, which compares below

any non-zero 'sectors', so the check is bypassed and the malformed

record is accepted.

The accepted mlcn is then used unchanged in

sbi->mft.lbo = mlcn << cluster_bits;

In practice the resulting reads fail at the block layer (sb_bread()

returns NULL via grow_buffers()'s check_mul_overflow() guard), so

today this manifests as mount fa

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References