{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-40233","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T07:20:57.180Z","datePublished":"2025-12-04T15:31:23.891Z","dateUpdated":"2026-08-05T12:08:43.055Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:08:43.055Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: clear extent cache after moving/defragmenting extents\n\nThe extent map cache can become stale when extents are moved or\ndefragmented, causing subsequent operations to see outdated extent flags. \nThis triggers a BUG_ON in ocfs2_refcount_cal_cow_clusters().\n\nThe problem occurs when:\n1. copy_file_range() creates a reflinked extent with OCFS2_EXT_REFCOUNTED\n2. ioctl(FITRIM) triggers ocfs2_move_extents()\n3. __ocfs2_move_extents_range() reads and caches the extent (flags=0x2)\n4. ocfs2_move_extent()/ocfs2_defrag_extent() calls __ocfs2_move_extent()\n   which clears OCFS2_EXT_REFCOUNTED flag on disk (flags=0x0)\n5. The extent map cache is not invalidated after the move\n6. Later write() operations read stale cached flags (0x2) but disk has\n   updated flags (0x0), causing a mismatch\n7. BUG_ON(!(rec->e_flags & OCFS2_EXT_REFCOUNTED)) triggers\n\nFix by clearing the extent map cache after each extent move/defrag\noperation in __ocfs2_move_extents_range().  This ensures subsequent\noperations read fresh extent data from disk."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerability is reached through the OCFS2_IOC_MOVE_EXT ioctl and a subsequent write()/read() on a local file descriptor, requiring local system access. No remote protocol handler is involved.\nAC:L - The trigger is a deterministic, fully attacker-controlled sequence (copy_file_range → OCFS2_IOC_MOVE_EXT → write) with no race window, no memory-layout dependency, and no reliance on any condition outside the attacker's control; syzbot reproduced it reliably.\nPR:L - OCFS2_IOC_MOVE_EXT has no capability check whatsoever (unlike FITRIM in the same switch which requires CAP_SYS_ADMIN); any unprivileged local user holding a writable fd on a regular file of a mounted ocfs2 volume can drive the whole sequence.\nUI:N - The attacker performs every step on its own file descriptor with no action by any other user; the ocfs2 mount is a pre-existing property of the deployment, not an action the attacker must induce.\nS:U - The corruption and crash are confined to the kernel and the filesystem's own on-disk data within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The stale extent-map entry retains the old physical cluster, which is freed to the global bitmap by the truncate-log flush at the end of the move, so later reads (O_DIRECT or buffered after cache eviction) resolve through the stale mapping and return the contents of clusters the allocator has since handed to other users' or root-owned files.\nI:H - The same stale cpos→old_phys mapping is used for writes and writeback, so attacker-controlled data lands on physical clusters now owned by a different file, giving arbitrary on-disk corruption of files the attacker has no write permission to.\nA:H - BUG_ON(!(rec->e_flags & OCFS2_EXT_REFCOUNTED)) at fs/ocfs2/refcounttree.c:2683 oopses the task while it holds inode_lock, ip_alloc_sem and the ocfs2 DLM inode lock, permanently wedging the filesystem and blocking other cluster nodes; with panic_on_oops it is a full system panic."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ocfs2/move_extents.c"],"versions":[{"version":"53069d4e76954e2e63c1b3c501051c6fbcf7298c","lessThan":"93166bc53c0e3587058327a4121daea34b4fecd5","status":"affected","versionType":"git"},{"version":"53069d4e76954e2e63c1b3c501051c6fbcf7298c","lessThan":"a7ee72286efba1d407c6f15a0528e43593fb7007","status":"affected","versionType":"git"},{"version":"53069d4e76954e2e63c1b3c501051c6fbcf7298c","lessThan":"93b1ab422f1966b71561158e1aedce4ec100f357","status":"affected","versionType":"git"},{"version":"53069d4e76954e2e63c1b3c501051c6fbcf7298c","lessThan":"e92af7737a94a729225d2a5d180eaaa77fe0bbc1","status":"affected","versionType":"git"},{"version":"53069d4e76954e2e63c1b3c501051c6fbcf7298c","lessThan":"aa6a21409dd6221bb268b56bb410e031c632ff9a","status":"affected","versionType":"git"},{"version":"53069d4e76954e2e63c1b3c501051c6fbcf7298c","lessThan":"bb69928ed578f881e68d26aaf1a8f6e7faab3b44","status":"affected","versionType":"git"},{"version":"53069d4e76954e2e63c1b3c501051c6fbcf7298c","lessThan":"a21750df2f6169af6e039a3bb4893d6c9564e48d","status":"affected","versionType":"git"},{"version":"53069d4e76954e2e63c1b3c501051c6fbcf7298c","lessThan":"78a63493f8e352296dbc7cb7b3f4973105e8679e","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ocfs2/move_extents.c"],"versions":[{"version":"3.0","status":"affected"},{"version":"0","lessThan":"3.0","status":"unaffected","versionType":"semver"},{"version":"5.4.301","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.246","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.196","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.158","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.115","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.56","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.17.6","lessThanOrEqual":"6.17.*","status":"unaffected","versionType":"semver"},{"version":"6.18","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"5.4.301"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"5.10.246"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"5.15.196"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"6.1.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"6.6.115"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"6.12.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"6.17.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"6.18"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/93166bc53c0e3587058327a4121daea34b4fecd5"},{"url":"https://git.kernel.org/stable/c/a7ee72286efba1d407c6f15a0528e43593fb7007"},{"url":"https://git.kernel.org/stable/c/93b1ab422f1966b71561158e1aedce4ec100f357"},{"url":"https://git.kernel.org/stable/c/e92af7737a94a729225d2a5d180eaaa77fe0bbc1"},{"url":"https://git.kernel.org/stable/c/aa6a21409dd6221bb268b56bb410e031c632ff9a"},{"url":"https://git.kernel.org/stable/c/bb69928ed578f881e68d26aaf1a8f6e7faab3b44"},{"url":"https://git.kernel.org/stable/c/a21750df2f6169af6e039a3bb4893d6c9564e48d"},{"url":"https://git.kernel.org/stable/c/78a63493f8e352296dbc7cb7b3f4973105e8679e"}],"title":"ocfs2: clear extent cache after moving/defragmenting extents","x_generator":{"engine":"bippy-1.2.0"}}}}