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CVE-2026-23234
f2fs: fix to avoid UAF in f2fs_write_end_io()
Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid UAF in f2fs_write_end_io() As syzbot reported an use-after-free issue in f2fs_write_end_io(). It is caused by below race condition: loop device umount - worker_thread - loop_process_work - do_req_filebacked - lo_rw_aio - lo_rw_aio_complete - blk_mq_end_request - blk_update_request - f2fs_write_end_io - dec_page_count - folio_end_writeback - kill_f2fs_super - kill_block_super - f2fs_put_super : free(sbi) : get_pages(, F2FS_WB_CP_DATA) accessed sbi which is freed In kill_f2fs_super(), we will drop all page caches of f2fs inodes before call free(sbi), it guarantee that all folios should end its writeback, so it should be safe to access sbi before last folio_end_writeback(). Let's relocate ckpt thread wakeup flow before folio_end_writeback() to resolve this issue.

INFO

Published Date :

March 4, 2026, 3:16 p.m.

Last Modified :

March 4, 2026, 6:08 p.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products

The following products are affected by CVE-2026-23234 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Solution
Resolve use-after-free by relocating checkpoint thread wakeup flow.
  • Relocate checkpoint thread wakeup flow.
  • Ensure folios end writeback before accessing memory.
  • Apply kernel patches to f2fs module.
  • Update Linux kernel to the latest version.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-23234.

URL Resource
https://git.kernel.org/stable/c/0fb58aff0dafd6837cc91f4154f3ed6e020358fa
https://git.kernel.org/stable/c/2f67ff1e15a8a4d0e4ffc6564ab20d03d7398fe9
https://git.kernel.org/stable/c/505e1c0530db6152cab3feef8e3e4da3d3e358c9
https://git.kernel.org/stable/c/995030be4ce6338c6ff814583c14166446a64008
https://git.kernel.org/stable/c/a42f99be8a16b32a0bb91bb6dda212a6ad61be5d
https://git.kernel.org/stable/c/acc2c97fc0005846e5cf11b5ba3189fef130c9b3
https://git.kernel.org/stable/c/ce2739e482bce8d2c014d76c4531c877f382aa54
https://git.kernel.org/stable/c/cf4a9e1bc8129eb63fda5f8bdcd8d87f0bd76f42
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-23234 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-23234 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-23234 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-23234 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Mar. 04, 2026

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid UAF in f2fs_write_end_io() As syzbot reported an use-after-free issue in f2fs_write_end_io(). It is caused by below race condition: loop device umount - worker_thread - loop_process_work - do_req_filebacked - lo_rw_aio - lo_rw_aio_complete - blk_mq_end_request - blk_update_request - f2fs_write_end_io - dec_page_count - folio_end_writeback - kill_f2fs_super - kill_block_super - f2fs_put_super : free(sbi) : get_pages(, F2FS_WB_CP_DATA) accessed sbi which is freed In kill_f2fs_super(), we will drop all page caches of f2fs inodes before call free(sbi), it guarantee that all folios should end its writeback, so it should be safe to access sbi before last folio_end_writeback(). Let's relocate ckpt thread wakeup flow before folio_end_writeback() to resolve this issue.
    Added Reference https://git.kernel.org/stable/c/0fb58aff0dafd6837cc91f4154f3ed6e020358fa
    Added Reference https://git.kernel.org/stable/c/2f67ff1e15a8a4d0e4ffc6564ab20d03d7398fe9
    Added Reference https://git.kernel.org/stable/c/505e1c0530db6152cab3feef8e3e4da3d3e358c9
    Added Reference https://git.kernel.org/stable/c/995030be4ce6338c6ff814583c14166446a64008
    Added Reference https://git.kernel.org/stable/c/a42f99be8a16b32a0bb91bb6dda212a6ad61be5d
    Added Reference https://git.kernel.org/stable/c/acc2c97fc0005846e5cf11b5ba3189fef130c9b3
    Added Reference https://git.kernel.org/stable/c/ce2739e482bce8d2c014d76c4531c877f382aa54
    Added Reference https://git.kernel.org/stable/c/cf4a9e1bc8129eb63fda5f8bdcd8d87f0bd76f42
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
No CVSS metrics available for this vulnerability.