---
id: CVE-2026-89839
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  f2fs: use the mount idmap for the owner check in f2fs_xattr_advise_set()

  f2fs_xattr_advise_set() calls inode_owner_or_capable() with &nop_mnt_idmap
  before allowing the…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  f2fs: use the mount idmap for the owner check in f2fs_xattr_advise_set()

  f2fs_xattr_advise_set() calls inode_owner_or_capable() with &nop_mnt_idmap
  before allowing the…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 01beba7957a26f9b7179127e8ad56bb5a0f56138 <
    4c0c610b480cfbc57528aa1acbd6be12ed2a6fb1
  - >-
    Linux >= 01beba7957a26f9b7179127e8ad56bb5a0f56138 <
    c3e2692c7a58e0bdb84bd658d827e89dcecea3ad
  - >-
    Linux >= 01beba7957a26f9b7179127e8ad56bb5a0f56138 <
    3b681229e9f8fb1dd29bc65983bf3c87779e4ca3
  - >-
    Linux >= 01beba7957a26f9b7179127e8ad56bb5a0f56138 <
    ab31e3b774f5d06b4489cef6c297b48c47c9dcbd
  - >-
    Linux >= 01beba7957a26f9b7179127e8ad56bb5a0f56138 <
    a54ffce4637acb0db8e695188a6c7f99f14c3576
  - Linux 6.3
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T11:16:50.727'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89839'
references:
  - url: 'https://git.kernel.org/stable/c/3b681229e9f8fb1dd29bc65983bf3c87779e4ca3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4c0c610b480cfbc57528aa1acbd6be12ed2a6fb1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a54ffce4637acb0db8e695188a6c7f99f14c3576'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ab31e3b774f5d06b4489cef6c297b48c47c9dcbd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c3e2692c7a58e0bdb84bd658d827e89dcecea3ad'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-16T10:53:53.997Z'
epss: 0.002
epssPercentile: 0.08783
---

## Overview

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

f2fs: use the mount idmap for the owner check in f2fs_xattr_advise_set()

f2fs_xattr_advise_set() calls inode_owner_or_capable() with &nop_mnt_idmap
before allowing the "system.advise" xattr to be set, instead of the idmap
that the VFS passes to the ->set() handler.

f2fs supports idmapped mounts, so on such a mount this checks the caller's
fsuid against the unmapped on-disk owner rather than the mapped owner: the
actual owner can be wrongly denied with -EPERM and an unrelated caller
wrongly allowed.  Pass the handler's idmap instead.

## Remediation

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