---
id: CVE-2026-45915
title: 'fat: avoid parent link count underflow in rmdir'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fat: avoid parent link count underflow in rmdir

  Corrupted FAT images can leave a directory inode with an incorrect
  i_nlink (e.g. 2 even though subdirectories exist). r…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 <
    7fe0de287e931e07cb96ecf1f449b2ebdb0e1115
  - >-
    Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 <
    9894c79fd9466612d0514be157b5c30cd93aa645
  - >-
    Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 <
    cd569b87378b9c33ae13c23d6bb9d205d66f7c4b
  - >-
    Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 <
    d3b7ffa90f613938128432c7b2f35b7aa4bdd86b
  - >-
    Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 <
    955c5d670b5ae07c78f4345e23a895638db96ce1
  - >-
    Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 <
    17866f8a0822d414cb02e621cf003a7d04396ef8
  - >-
    Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 <
    d0bb592fa9def2bace90ac8926c0a1d6fa8c1aa0
  - >-
    Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 <
    8cafcb881364af5ef3a8b9fed4db254054033d8a
  - Linux 2.6.19
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T15:44:21.682551Z'
published: '2026-05-27'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T15:53:12.556Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-45915'
references:
  - url: 'https://git.kernel.org/stable/c/7fe0de287e931e07cb96ecf1f449b2ebdb0e1115'
  - url: 'https://git.kernel.org/stable/c/9894c79fd9466612d0514be157b5c30cd93aa645'
  - url: 'https://git.kernel.org/stable/c/cd569b87378b9c33ae13c23d6bb9d205d66f7c4b'
  - url: 'https://git.kernel.org/stable/c/d3b7ffa90f613938128432c7b2f35b7aa4bdd86b'
  - url: 'https://git.kernel.org/stable/c/955c5d670b5ae07c78f4345e23a895638db96ce1'
  - url: 'https://git.kernel.org/stable/c/17866f8a0822d414cb02e621cf003a7d04396ef8'
  - url: 'https://git.kernel.org/stable/c/d0bb592fa9def2bace90ac8926c0a1d6fa8c1aa0'
  - url: 'https://git.kernel.org/stable/c/8cafcb881364af5ef3a8b9fed4db254054033d8a'
tags:
  - cve.org
epss: 0.0016
epssPercentile: 0.0526
ingestedAt: '2026-11-06T16:57:43.387Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

fat: avoid parent link count underflow in rmdir

Corrupted FAT images can leave a directory inode with an incorrect
i_nlink (e.g. 2 even though subdirectories exist). rmdir then
unconditionally calls drop_nlink(dir) and can drive i_nlink to 0,
triggering the WARN_ON in drop_nlink().

Add a sanity check in vfat_rmdir() and msdos_rmdir(): only drop the
parent link count when it is at least 3, otherwise report a filesystem
error.

## Affected

- `Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 < 7fe0de287e931e07cb96ecf1f449b2ebdb0e1115`
- `Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 < 9894c79fd9466612d0514be157b5c30cd93aa645`
- `Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 < cd569b87378b9c33ae13c23d6bb9d205d66f7c4b`
- `Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 < d3b7ffa90f613938128432c7b2f35b7aa4bdd86b`
- `Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 < 955c5d670b5ae07c78f4345e23a895638db96ce1`
- `Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 < 17866f8a0822d414cb02e621cf003a7d04396ef8`
- `Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 < d0bb592fa9def2bace90ac8926c0a1d6fa8c1aa0`
- `Linux >= 9a53c3a783c2fa9b969628e65695c11c3e51e673 < 8cafcb881364af5ef3a8b9fed4db254054033d8a`
- `Linux 2.6.19`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.