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CVE-2026-98135

ntfs: reject invalid sectors_per_cluster in the boot sector

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 7.2.7
None on Exploit-DB, Metasploit or GitHub

Summary

In the Linux kernel, the following vulnerability has been resolved: ntfs: reject invalid sectors_per_cluster in the boot sector is_boot_sector_ntfs() checks the boot sector's sectors_per_cluster field with a range test that rejects 0x81..0xf3 but accepts 0 and other non-power-of-two counts. A zero value reaches parse_ntfs_boot_sector(): sectors_per_cluster_bits = ffs(sectors_per_cluster) - 1; ... vol->cluster_size = vol->sector_size << sectors_per_cluster_bits; ffs(0) is 0, so sectors_per_cluster_bits becomes (unsigned)-1 and the shift is undefined: UBSAN: shift-out-of-bounds in fs/ntfs/super.c:673:39 shift exponent 4294967295 is too large for 32-bit type 'int' This change rejects any non-power-of-two value, since it feeds the aforementioned shift via ffs() - 1, which only yields the correct shift for a power of two.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 6251f0b0de7d645e3591931ca4c11d8322c1866f · fixed in 7524c3145a3bac92bebbc47a29c007f1d874c9b3; From 6251f0b0de7d645e3591931ca4c11d8322c1866f · fixed in 323751a604e7533fa473874d999371592a614207

  • Linux Linux

    7.1

  • KernelLinux

    From 7.1.0 · fixed in 7.2.7

References 2

git.kernel.org