DEBIAN-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The extent map cache can become stale when extents are moved or defragmented, causing subsequent operations to see outdated extent flags.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.
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Debian:11 | linux | 5.10.84-1, *, 5.10.234-1 |
| Debian:14 | linux | 6.16.11-1, 6.16.12-1, 6.16.12-1 |
| Debian:13 | linux | *, 0, 6.12.38-1 |
| Debian:12 | linux | 6.1.106-2, 6.1.99-1, 6.1.98-1 |
Exploit Intelligence
- 4081.3.7.yml (github-poc)
Timeline
- Dec 4, 2025 CVE Published
- Apr 28, 2026 CVE Updated