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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-90200

fs/ntfs3: fix integer overflow in MFT cluster validation

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Status
Published
Published
Updated
Assigning organization
Linux

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

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 82cae269cfa953032fbb8980a7d554d60fb00b17 to < f77a8d9fdf58e298b36564a44c27fadc617bdd28affected
  • 82cae269cfa953032fbb8980a7d554d60fb00b17 to < 805cc5554b13d045dce9b03c13eaf015418739fdaffected
  • 82cae269cfa953032fbb8980a7d554d60fb00b17 to < dc6d85de7e2656e56e10ff5ba514f2583a4f612baffected
  • 82cae269cfa953032fbb8980a7d554d60fb00b17 to < 169383d8914b8fe03464a83540b5b6de3e7831afaffected
  • 82cae269cfa953032fbb8980a7d554d60fb00b17 to < c510c63873103a5da6a498fe537bdb5d6f8d03a2affected

Linux Linux

Default version status: affected

  • 5.15affected
  • 0 to < 5.15unaffected
  • 6.6.157 to ≤ 6.6.*unaffected
  • 6.12.110 to ≤ 6.12.*unaffected
  • 6.18.52 to ≤ 6.18.*unaffected
  • 7.2.6 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References