fs/ntfs3: fix integer overflow in MFT cluster validation

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-90200
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 17:17:14 UTC
Updated2026-09-17 17:17:14 UTC
DescriptionIn 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.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 f77a8d9fdf58e298b36564a44c27fadc617bdd28 git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 805cc5554b13d045dce9b03c13eaf015418739fd git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 dc6d85de7e2656e56e10ff5ba514f2583a4f612b git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 169383d8914b8fe03464a83540b5b6de3e7831af git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 c510c63873103a5da6a498fe537bdb5d6f8d03a2 git Not specified
CNA Linux Linux affected 5.15 Not specified
CNA Linux Linux unaffected 5.15 semver Not specified
CNA Linux Linux unaffected 6.6.157 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.52 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.6 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/169383d8914b8fe03464a83540b5b6de3e7831af 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f77a8d9fdf58e298b36564a44c27fadc617bdd28 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/dc6d85de7e2656e56e10ff5ba514f2583a4f612b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/805cc5554b13d045dce9b03c13eaf015418739fd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c510c63873103a5da6a498fe537bdb5d6f8d03a2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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