CVE-2026-23234

Kernel memory corruption via F2FS unmount race

Published Mar 4, 2026 · Updated Mar 4, 2026

Use-after-free in the F2FS write-completion path in Linux Kernel allows local users to access freed kernel memory during concurrent I/O and unmount. f2fs_write_end_io() ends folio writeback before waking the checkpoint thread, allowing f2fs_put_super() to free superblock state before get_pages() reads it. The race requires CAP_SYS_ADMIN in the initial user namespace, an F2FS-capable block device, and concurrent unmount activity; successful exploitation reads or modifies kernel memory or crashes the system.

CVSS severity7.8
High
EPSS probability0.12%
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 F2FS write-completion path in Linux Kernel allows local users to access freed kernel memory during concurrent I/O and unmount. f2fs_write_end_io() ends folio writeback before waking the checkpoint thread, allowing f2fs_put_super() to free superblock state before get_pages() reads it. The race requires CAP_SYS_ADMIN in the initial user namespace, an F2FS-capable block device, and concurrent unmount activity; successful exploitation reads or modifies kernel memory or crashes the system.

The record

CVE
CVE-2026-23234
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Mar 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 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=3.13
  2. Affected versionversion=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <0fb58aff0dafd6837cc91f4154f3ed6e020358fa
  3. Affected versionversion=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <2f67ff1e15a8a4d0e4ffc6564ab20d03d7398fe9
  4. Affected versionversion=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <505e1c0530db6152cab3feef8e3e4da3d3e358c9
  5. Affected versionversion=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <995030be4ce6338c6ff814583c14166446a64008
  6. Affected versionversion=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <a42f99be8a16b32a0bb91bb6dda212a6ad61be5d
  7. Affected versionversion=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <acc2c97fc0005846e5cf11b5ba3189fef130c9b3
  8. Affected versionversion=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <ce2739e482bce8d2c014d76c4531c877f382aa54
  9. Affected versionversion=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <cf4a9e1bc8129eb63fda5f8bdcd8d87f0bd76f42

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.13; version=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <0fb58aff0dafd6837cc91f4154f3ed6e020358fa; version=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <2f67ff1e15a8a4d0e4ffc6564ab20d03d7398fe9; version=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <505e1c0530db6152cab3feef8e3e4da3d3e358c9; version=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <995030be4ce6338c6ff814583c14166446a64008; version=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <a42f99be8a16b32a0bb91bb6dda212a6ad61be5d; version=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <acc2c97fc0005846e5cf11b5ba3189fef130c9b3; version=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <ce2739e482bce8d2c014d76c4531c877f382aa54; version=e234088758fca3a669ebb1a02d8bf7bf60f0e4ff <cf4a9e1bc8129eb63fda5f8bdcd8d87f0bd76f42

Published CVSS scores

7.8CanonicalCVSS:3.1/AV:L/AC:L/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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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