---
id: CVE-2026-63818
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  f2fs: validate orphan inode entry count

  f2fs_recover_orphan_inodes() trusts the orphan block entry_count when
  replaying orphan inodes from the checkpoint pack
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  f2fs: validate orphan inode entry count

  f2fs_recover_orphan_inodes() trusts the orphan block entry_count when
  replaying orphan inodes from the checkpoint pack. A corru…
severity: high
cvss: 8.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
published: '2026-07-19'
updated: '2026-08-17'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63818'
references:
  - url: 'https://git.kernel.org/stable/c/210c210c92d78fdf5051bc55c5c69044b1a2150a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2e12381d4495dc8b0ff042c6856022b2e359835c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/550511a2470f6d204fa07b331f048bd2d3c51280'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/846c499a65816d13f1186e3090e825e8bb8bcb8b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8aad54746c251f2c2370118df766c0c82e2d2091'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ad101d15716f5a24d1fa82a849f80430c805a3dd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d18c81f5d0ecd5796aa47d66d98f2dd54d8d0f70'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d2f236196d542ccd8505736e41c3a1d3f0305f6f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.0014
epssPercentile: 0.02718
ingestedAt: '2026-08-17T05:47:49.665Z'
---

## Overview

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

f2fs: validate orphan inode entry count

f2fs_recover_orphan_inodes() trusts the orphan block entry_count when
replaying orphan inodes from the checkpoint pack. A corrupted entry_count
larger than F2FS_ORPHANS_PER_BLOCK makes the recovery loop read past the
ino[] array and interpret footer or following data as inode numbers.

On a crafted image, mounting an unpatched kernel can drive orphan recovery
into f2fs_bug_on() and panic the kernel. Validate entry_count before
consuming entries so corrupted checkpoint data fails the mount with
-EFSCORRUPTED and requests fsck instead.

Set ERROR_INCONSISTENT_ORPHAN as well, so the corruption reason can be
recorded in the superblock s_errors[] field. This gives fsck a persistent
hint even though mount-time orphan recovery failure may leave no chance to
persist SBI_NEED_FSCK through a checkpoint.

## Remediation

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