CVE-2025-40233: In the Linux kernel, the following vulnerability has been resolved: ocfs2: clear extent cache after moving/defragmenting extents The extent map cach...

Description

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The extent map cache can become stale when extents are moved or defragmented, causing subsequent operations to see outdated extent flags.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.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.19%

8.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 53069d4e76954e2e63c1b3c501051c6fbcf7298c, < 93166bc53c0e3587058327a4121daea34b4fecd5; >= 53069d4e76954e2e63c1b3c501051c6fbcf7298c, < a7ee72286efba1d407c6f15a0528e43593fb7007; >= 53069d4e76954e2e63c1b3c501051c6fbcf7298c, < 93b1ab422f1966b71561158e1aedce4ec100f357; >= 53069d4e76954e2e63c1b3c501051c6fbcf7298c, < e92af7737a94a729225d2a5d180eaaa77fe0bbc1; >= 53069d4e76954e2e63c1b3c501051c6fbcf7298c, < aa6a21409dd6221bb268b56bb410e031c632ff9a; >= 53069d4e76954e2e63c1b3c501051c6fbcf7298c, < bb69928ed578f881e68d26aaf1a8f6e7faab3b44; >= 53069d4e76954e2e63c1b3c501051c6fbcf7298c, < a21750df2f6169af6e039a3bb4893d6c9564e48d; >= 53069d4e76954e2e63c1b3c501051c6fbcf7298c, < 78a63493f8e352296dbc7cb7b3f4973105e8679e
Linux	Linux	3.0

References

Timeline

Published: Dec 4, 2025
Last Modified: Jul 30, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-40233?

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.

How severe is CVE-2025-40233?

CVE-2025-40233 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2025-40233?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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