CVE-2026-90200

fs/ntfs3: fix integer overflow in MFT cluster validation

Published Sep 17, 2026 CVSS n/a EPSS < 1% KEV · Not listed

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 failing in odd places rather than as
something more dangerous, but the validation step is still wrong
and there is no reason for callers to rely on the block layer to
catch a value that should never have been accepted in the first
place.

Use check_mul_overflow() to compute the two sector positions and
fail the mount if either multiplication wraps; this preserves the
existing semantics (mlcn * sct_per_clst >= sectors) instead of
switching to division (mlcn >= sectors / sct_per_clst), which
would tighten the check at edge cases where 'sectors' is not a
multiple of sct_per_clst. The check_*_overflow() style is the
one ntfs3 already uses for similar on-disk arithmetic in
fs/ntfs3/run.c.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`82cae269cfa953032fbb8980a7d554d60fb00b17`	affected	< 8ecb1525a9520acd3d5ea3e2593e487fd9f143ce
`82cae269cfa953032fbb8980a7d554d60fb00b17`	affected	< f77a8d9fdf58e298b36564a44c27fadc617bdd28
`82cae269cfa953032fbb8980a7d554d60fb00b17`	affected	< 805cc5554b13d045dce9b03c13eaf015418739fd
`82cae269cfa953032fbb8980a7d554d60fb00b17`	affected	< dc6d85de7e2656e56e10ff5ba514f2583a4f612b
`82cae269cfa953032fbb8980a7d554d60fb00b17`	affected	< 169383d8914b8fe03464a83540b5b6de3e7831af
`82cae269cfa953032fbb8980a7d554d60fb00b17`	affected	< c510c63873103a5da6a498fe537bdb5d6f8d03a2

Linux

affected

Version	Status	Constraints
`5.15`	affected	—
`0`	unaffected	< 5.15
`6.1.191`	unaffected	≤ 6.1.*
`6.6.157`	unaffected	≤ 6.6.*
`6.12.110`	unaffected	≤ 6.12.*
`6.18.52`	unaffected	≤ 6.18.*
`7.2.6`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Versions

Linux

Linux Kernel

Version	Status	Scheme	Platform
`[82cae269cfa953032fbb8980a7d554d60fb00b17,f77a8d9fdf58e298b36564a44c27fadc617bdd28)`	affected	code_commit	—
`[82cae269cfa953032fbb8980a7d554d60fb00b17,805cc5554b13d045dce9b03c13eaf015418739fd)`	affected	code_commit	—
`[82cae269cfa953032fbb8980a7d554d60fb00b17,dc6d85de7e2656e56e10ff5ba514f2583a4f612b)`	affected	code_commit	—
`[82cae269cfa953032fbb8980a7d554d60fb00b17,169383d8914b8fe03464a83540b5b6de3e7831af)`	affected	code_commit	—
`[82cae269cfa953032fbb8980a7d554d60fb00b17,c510c63873103a5da6a498fe537bdb5d6f8d03a2)`	affected	code_commit	—

Linux

Linux Kernel

Version	Status	Scheme	Platform
`5.15`	affected	semver	—
`[0,5.15)`	unaffected	semver	—
`[6.6.157,6.7.0)`	unaffected	semver	—
`[6.12.110,6.13.0)`	unaffected	semver	—
`[6.18.52,6.19.0)`	unaffected	semver	—
`[7.2.6,7.3.0)`	unaffected	semver	—
`[7.3-rc1,*]`	unaffected	generic	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
Debian DLA	DLA-4817-1	linux-6.12 security update
Debian DSA	DSA-6528-1	linux security update
Ubuntu USN	USN-9019-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9020-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9022-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9023-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9024-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9025-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9026-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9039-1	Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN	USN-9040-1	Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN	USN-9066-1	Linux kernel (HWE) vulnerabilities
Ubuntu USN	USN-9091-1	Linux kernel (NVIDIA Tegra) vulnerabilities

Metrics

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.225% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/169383d8914b8fe03464a83540b5b6de3e7831af
https://git.kernel.org/stable/c/805cc5554b13d045dce9b03c13eaf015418739fd
https://git.kernel.org/stable/c/8ecb1525a9520acd3d5ea3e2593e487fd9f143ce
https://git.kernel.org/stable/c/c510c63873103a5da6a498fe537bdb5d6f8d03a2
https://git.kernel.org/stable/c/dc6d85de7e2656e56e10ff5ba514f2583a4f612b
https://git.kernel.org/stable/c/f77a8d9fdf58e298b36564a44c27fadc617bdd28

History

Oct 30, 2026 12:45 PM Added references View changes

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/8ecb1525a9520acd3d5ea3e2593e487fd9f143ce

Sep 20, 2026 2:00 AM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-680

Sep 17, 2026 4:30 PM Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references View changes

Type	Values Removed	Values Added
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 failing in odd places rather than as something more dangerous, but the validation step is still wrong and there is no reason for callers to rely on the block layer to catch a value that should never have been accepted in the first place. Use check_mul_overflow() to compute the two sector positions and fail the mount if either multiplication wraps; this preserves the existing semantics (mlcn * sct_per_clst >= sectors) instead of switching to division (mlcn >= sectors / sct_per_clst), which would tighten the check at edge cases where 'sectors' is not a multiple of sct_per_clst. The check_*_overflow() style is the one ntfs3 already uses for similar on-disk arithmetic in fs/ntfs3/run.c.
Title		fs/ntfs3: fix integer overflow in MFT cluster validation
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/169383d8914b8fe03464a83540b5b6de3e7831af https://git.kernel.org/stable/c/805cc5554b13d045dce9b03c13eaf015418739fd https://git.kernel.org/stable/c/c510c63873103a5da6a498fe537bdb5d6f8d03a2 https://git.kernel.org/stable/c/dc6d85de7e2656e56e10ff5ba514f2583a4f612b https://git.kernel.org/stable/c/f77a8d9fdf58e298b36564a44c27fadc617bdd28