CVE-2026-23234

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.

PUBLISHED Reserved 2026-01-13 | Published 2026-03-04 | Updated 2026-03-04 | Assigner Linux

Product status

References

git.kernel.org/...c/0fb58aff0dafd6837cc91f4154f3ed6e020358fa

git.kernel.org/...c/2f67ff1e15a8a4d0e4ffc6564ab20d03d7398fe9

git.kernel.org/...c/505e1c0530db6152cab3feef8e3e4da3d3e358c9

git.kernel.org/...c/acc2c97fc0005846e5cf11b5ba3189fef130c9b3

git.kernel.org/...c/cf4a9e1bc8129eb63fda5f8bdcd8d87f0bd76f42

git.kernel.org/...c/995030be4ce6338c6ff814583c14166446a64008

git.kernel.org/...c/a42f99be8a16b32a0bb91bb6dda212a6ad61be5d

git.kernel.org/...c/ce2739e482bce8d2c014d76c4531c877f382aa54

cve.org (CVE-2026-23234)

nvd.nist.gov (CVE-2026-23234)

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