# CVE-2026-98135: linux: In the Linux kernel, the following vulnerability has been resolved:  ntfs: reject invalid sectors_per_cluster in the...

CVE-2026-98135 is fixed in linux on 1 platform by DEBIAN-CVE-2026-98135 (version 7.2.7-1), released October 2, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-98135
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0010
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 25, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.7-1 | [DEBIAN-CVE-2026-98135](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98135.md) | Oct 2, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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