7.8

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

Analyzed
AliasesUBUNTU-CVE-2026-23234DEBIAN-CVE-2026-23234
Published 04-03-2026Last modified 11-05-2026

Vulnerability summary

CVE-2026-23234 is a high (CVSS 7.8) Use After Free vulnerability in linux. EPSS estimates a 0.14% chance of exploitation in the next 30 days, higher than 3.1% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.8/10
010
High · v3.1 (NVD)
EPSS score
0.14%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 31 · Related 25
DLA-4498-1DLA-4499-1DSA-6162-1DSA-6163-1MGASA-2026-0097MGASA-2026-0098

Timeline

  1. 04-03-2026
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.14%

Chance of exploitation in the next 30 days

Percentile

3%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.12% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu157 products
  • linuxAll versions (No fix recorded) | < 5.15.0-186.196 | < 6.8.0-134.134
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1112.119 | < 6.8.0-1060.63
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ e234088758fca3a669ebb1a02d8bf7bf60f0e4ff, < 0fb58aff0dafd6837cc91f4154f3ed6e020358fa | ≥ e234088758fca3a669ebb1a02d8bf7bf60f0e4ff, < 2f67ff1e15a8a4d0e4ffc6564ab20d03d7398fe9 | ≥ e234088758fca3a669ebb1a02d8bf7bf60f0e4ff, < 505e1c0530db6152cab3feef8e3e4da3d3e358c9 | ≥ e234088758fca3a669ebb1a02d8bf7bf60f0e4ff, < acc2c97fc0005846e5cf11b5ba3189fef130c9b3 | ≥ e234088758fca3a669ebb1a02d8bf7bf60f0e4ff, < cf4a9e1bc8129eb63fda5f8bdcd8d87f0bd76f42 | ≥ e234088758fca3a669ebb1a02d8bf7bf60f0e4ff, < 995030be4ce6338c6ff814583c14166446a64008 | ≥ e234088758fca3a669ebb1a02d8bf7bf60f0e4ff, < a42f99be8a16b32a0bb91bb6dda212a6ad61be5d | ≥ e234088758fca3a669ebb1a02d8bf7bf60f0e4ff, < ce2739e482bce8d2c014d76c4531c877f382aa54 | 3.13
  • linux_kernel≥ 3.13, < 5.10.251 | ≥ 5.11, < 5.15.201 | ≥ 5.16, < 6.1.164 | ≥ 6.2, < 6.6.127 | ≥ 6.7, < 6.12.74 | ≥ 6.13, < 6.18.13 | ≥ 6.19, < 6.19.3
Debian1 product
  • linux< 6.1.164-1 | < 6.12.74-2 | < 6.18.13-1

3 vendors · 160 products

References

36 links
Show all 36 references