Use After Free Affecting kernel-uek-doc package, versions <0:6.12.0-200.74.27.el9uek


Severity

Recommended
0.0
high
0
10

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.02% (4th percentile)

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  • Snyk IDSNYK-ORACLE9-KERNELUEKDOC-15866007
  • published1 Apr 2026
  • disclosed4 Mar 2026

Introduced: 4 Mar 2026

CVE-2026-23234  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Oracle:9 kernel-uek-doc to version 0:6.12.0-200.74.27.el9uek or higher.
This issue was patched in ELSA-2026-50160.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-uek-doc package and not the kernel-uek-doc package as distributed by Oracle. See How to fix? for Oracle:9 relevant fixed versions and status.

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 Base Scores

version 3.1