CVE-2025-21811

Local kernel memory corruption via unlocked buffer walk

Published Feb 27, 2025 · Updated Aug 5, 2026

Use-after-free in the nilfs2 filesystem in affected Linux kernel releases allows local users to corrupt kernel memory via file operations. nilfs_lookup_dirty_data_buffers() walks buffer heads without locking the owning folio, while asynchronous dirty-state clearing lets try_to_free_buffers() release those buffers during the walk. Reachability requires write access to a mounted nilfs2 volume as it degenerates to read-only; successful exploitation can crash the kernel or compromise its memory.

CVSS severity7.8
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the nilfs2 filesystem in affected Linux kernel releases allows local users to corrupt kernel memory via file operations. nilfs_lookup_dirty_data_buffers() walks buffer heads without locking the owning folio, while asynchronous dirty-state clearing lets try_to_free_buffers() release those buffers during the walk. Reachability requires write access to a mounted nilfs2 volume as it degenerates to read-only; successful exploitation can crash the kernel or compromise its memory.

The record

CVE
CVE-2025-21811
Published
Feb 27, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Feb 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.10
  2. Affected versionversion=8c26c4e2694a163d525976e804d81cd955bbb40c <367a9bffabe08c04f6d725032cce3d891b2b9e1a
  3. Affected versionversion=8c26c4e2694a163d525976e804d81cd955bbb40c <4b08d23d7d1917bef4fbee8ad81372f49b006656
  4. Affected versionversion=8c26c4e2694a163d525976e804d81cd955bbb40c <58c27fa7a610b6e8d44e6220e7dbddfbaccaf439
  5. Affected versionversion=8c26c4e2694a163d525976e804d81cd955bbb40c <72cf688d0ce7e642b12ddc9b2a42524737ec1b4a
  6. Affected versionversion=8c26c4e2694a163d525976e804d81cd955bbb40c <8e1b9201c9a24638cf09c6e1c9f224157328010b
  7. Affected versionversion=8c26c4e2694a163d525976e804d81cd955bbb40c <c437dfac9f7a5a46ac2a5e6d6acd3059e9f68188
  8. Affected versionversion=8c26c4e2694a163d525976e804d81cd955bbb40c <d8ff250e085a4c4cdda4ad1cdd234ed110393143
  9. Affected versionversion=8c26c4e2694a163d525976e804d81cd955bbb40c <e1fc4a90a90ea8514246c45435662531975937d9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=3.10; version=8c26c4e2694a163d525976e804d81cd955bbb40c <367a9bffabe08c04f6d725032cce3d891b2b9e1a; version=8c26c4e2694a163d525976e804d81cd955bbb40c <4b08d23d7d1917bef4fbee8ad81372f49b006656; version=8c26c4e2694a163d525976e804d81cd955bbb40c <58c27fa7a610b6e8d44e6220e7dbddfbaccaf439; version=8c26c4e2694a163d525976e804d81cd955bbb40c <72cf688d0ce7e642b12ddc9b2a42524737ec1b4a; version=8c26c4e2694a163d525976e804d81cd955bbb40c <8e1b9201c9a24638cf09c6e1c9f224157328010b; version=8c26c4e2694a163d525976e804d81cd955bbb40c <c437dfac9f7a5a46ac2a5e6d6acd3059e9f68188; version=8c26c4e2694a163d525976e804d81cd955bbb40c <d8ff250e085a4c4cdda4ad1cdd234ed110393143; version=8c26c4e2694a163d525976e804d81cd955bbb40c <e1fc4a90a90ea8514246c45435662531975937d9

Published CVSS scores

7.8Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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