CVE-2025-40233 Affecting kernel-uek-doc package, versions <0:5.4.17-2136.350.3.1.el8uek


Severity

Recommended
high

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.05% (17th percentile)

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  • Snyk IDSNYK-ORACLE8-KERNELUEKDOC-14409407
  • published13 Dec 2025
  • disclosed4 Dec 2025

Introduced: 4 Dec 2025

CVE-2025-40233  (opens in a new tab)

How to fix?

Upgrade Oracle:8 kernel-uek-doc to version 0:5.4.17-2136.350.3.1.el8uek or higher.
This issue was patched in ELSA-2025-28049.

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:8 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

ocfs2: clear extent cache after moving/defragmenting extents

The extent map cache can become stale when extents are moved or defragmented, causing subsequent operations to see outdated extent flags. This triggers a BUG_ON in ocfs2_refcount_cal_cow_clusters().

The problem occurs when:

  1. copy_file_range() creates a reflinked extent with OCFS2_EXT_REFCOUNTED
  2. ioctl(FITRIM) triggers ocfs2_move_extents()
  3. __ocfs2_move_extents_range() reads and caches the extent (flags=0x2)
  4. ocfs2_move_extent()/ocfs2_defrag_extent() calls __ocfs2_move_extent() which clears OCFS2_EXT_REFCOUNTED flag on disk (flags=0x0)
  5. The extent map cache is not invalidated after the move
  6. Later write() operations read stale cached flags (0x2) but disk has updated flags (0x0), causing a mismatch
  7. BUG_ON(!(rec->e_flags & OCFS2_EXT_REFCOUNTED)) triggers

Fix by clearing the extent map cache after each extent move/defrag operation in __ocfs2_move_extents_range(). This ensures subsequent operations read fresh extent data from disk.

CVSS Base Scores

version 3.1