{"id":"CVE-2026-89496","title":"ocfs2: always run deallocs on copy-on-write completion","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: always run deallocs on copy-on-write completion\n\nLocal fuzzing of 6.12.94 has found the following memory leak\ncaused by doing 'copy_file_range()' within the same…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-772"],"vendor":"Linux","product":"Linux","affected":["Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 5ff30f07def6d0e6edacf47952807b5ff60f3af6","Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 2753e12853ed2023555cec2c5fe22fbaabb2c0b7","Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < f0261b3aca027f5c409a402ea22f6982750f911c","Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < a4adaa722977f46511d4247172cd4ec991b80ff2","Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 123c050eb96aae0bab74c9f06c6ad3de7992722b","Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 71f07b7f90b3109c9098d1b9c8efbbeece5deb8a","Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 09e93a60e18e83a630ff84ae00cb564bab96ab1f","Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 82ea9d4fc05fb7a387db547c6a7c0aa6a3719616","Linux 2.6.32"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:47:47.928Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89496","references":[{"url":"https://git.kernel.org/stable/c/5ff30f07def6d0e6edacf47952807b5ff60f3af6"},{"url":"https://git.kernel.org/stable/c/2753e12853ed2023555cec2c5fe22fbaabb2c0b7"},{"url":"https://git.kernel.org/stable/c/f0261b3aca027f5c409a402ea22f6982750f911c"},{"url":"https://git.kernel.org/stable/c/a4adaa722977f46511d4247172cd4ec991b80ff2"},{"url":"https://git.kernel.org/stable/c/123c050eb96aae0bab74c9f06c6ad3de7992722b"},{"url":"https://git.kernel.org/stable/c/71f07b7f90b3109c9098d1b9c8efbbeece5deb8a"},{"url":"https://git.kernel.org/stable/c/09e93a60e18e83a630ff84ae00cb564bab96ab1f"},{"url":"https://git.kernel.org/stable/c/82ea9d4fc05fb7a387db547c6a7c0aa6a3719616"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89496.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89496"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532512"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89496"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89496"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89496.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00177,"epssPercentile":0.07177,"ingestedAt":"2026-09-14T15:23:07.452Z","slug":"CVE-2026-89496","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: always run deallocs on copy-on-write completion\n\nLocal fuzzing of 6.12.94 has found the following memory leak\ncaused by doing 'copy_file_range()' within the same filesystem:\n\nunreferenced object 0xffff88812192c980 (size 32):\n  comm \"syz.0.49\", pid 12095, jiffies 4294964143\n  hex dump (first 32 bytes):\n    00 00 00 00 00 00 00 00 08 00 00 00 00 00 00 00  ................\n    c0 c5 92 21 81 88 ff ff 00 02 00 00 00 06 00 00  ...!............\n  backtrace (crc 7068d63f):\n    kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline]\n    slab_post_alloc_hook mm/slub.c:4152 [inline]\n    slab_alloc_node mm/slub.c:4197 [inline]\n    __kmalloc_cache_noprof+0x168/0x2c0 mm/slub.c:4358\n    kmalloc_noprof include/linux/slab.h:878 [inline]\n    ocfs2_find_per_slot_free_list fs/ocfs2/alloc.c:6618 [inline]\n    ocfs2_cache_block_dealloc+0x155/0x4b0 fs/ocfs2/alloc.c:6786\n    ocfs2_cache_extent_block_free fs/ocfs2/alloc.c:6819 [inline]\n    ocfs2_unlink_path+0x286/0x450 fs/ocfs2/alloc.c:2613\n    ocfs2_rotate_subtree_left fs/ocfs2/alloc.c:2779 [inline]\n    __ocfs2_rotate_tree_left+0x1f6f/0x2da0 fs/ocfs2/alloc.c:2985\n    ocfs2_rotate_tree_left+0x283/0xe00 fs/ocfs2/alloc.c:3237\n    ocfs2_try_to_merge_extent+0xf56/0x1a20 fs/ocfs2/alloc.c:3825\n    ocfs2_split_extent+0x15f4/0x2940 fs/ocfs2/alloc.c:5138\n    ocfs2_clear_ext_refcount+0x2f6/0x550 fs/ocfs2/refcounttree.c:3098\n    ocfs2_replace_clusters fs/ocfs2/refcounttree.c:3131 [inline]\n    ocfs2_make_clusters_writable fs/ocfs2/refcounttree.c:3255 [inline]\n    ocfs2_replace_cow+0x991/0x1660 fs/ocfs2/refcounttree.c:3349\n    ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3427 [inline]\n    ocfs2_refcount_cow+0x5e1/0x9f0 fs/ocfs2/refcounttree.c:3470\n    ocfs2_prepare_inode_for_write fs/ocfs2/file.c:2340 [inline]\n    ocfs2_file_write_iter+0xbda/0x1880 fs/ocfs2/file.c:2451\n    iter_file_splice_write+0x890/0xf60 fs/splice.c:743\n    do_splice_from fs/splice.c:944 [inline]\n    direct_splice_actor+0x232/0x480 fs/splice.c:1167\n    splice_direct_to_actor+0x4b4/0xb60 fs/splice.c:1111\n    do_splice_direct_actor fs/splice.c:1210 [inline]\n    do_splice_direct+0x10f/0x1c0 fs/splice.c:1236\n    do_sendfile+0x430/0xbf0 fs/read_write.c:1388\n\nunreferenced object 0xffff88812192c5c0 (size 32):\n  comm \"syz.0.49\", pid 12095, jiffies 4294964143\n  hex dump (first 32 bytes):\n    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n    29 70 00 00 00 00 00 00 19 00 00 00 00 00 00 00  )p..............\n  backtrace (crc afec850f):\n    kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline]\n    slab_post_alloc_hook mm/slub.c:4152 [inline]\n    slab_alloc_node mm/slub.c:4197 [inline]\n    __kmalloc_cache_noprof+0x168/0x2c0 mm/slub.c:4358\n    kmalloc_noprof include/linux/slab.h:878 [inline]\n    kzalloc_noprof include/linux/slab.h:1014 [inline]\n    ocfs2_cache_block_dealloc+0x25c/0x4b0 fs/ocfs2/alloc.c:6793\n    ocfs2_cache_extent_block_free fs/ocfs2/alloc.c:6819 [inline]\n    ocfs2_unlink_path+0x286/0x450 fs/ocfs2/alloc.c:2613\n    ocfs2_rotate_subtree_left fs/ocfs2/alloc.c:2779 [inline]\n    __ocfs2_rotate_tree_left+0x1f6f/0x2da0 fs/ocfs2/alloc.c:2985\n    ocfs2_rotate_tree_left+0x283/0xe00 fs/ocfs2/alloc.c:3237\n    ocfs2_try_to_merge_extent+0xf56/0x1a20 fs/ocfs2/alloc.c:3825\n    ocfs2_split_extent+0x15f4/0x2940 fs/ocfs2/alloc.c:5138\n    ocfs2_clear_ext_refcount+0x2f6/0x550 fs/ocfs2/refcounttree.c:3098\n    ocfs2_replace_clusters fs/ocfs2/refcounttree.c:3131 [inline]\n    ocfs2_make_clusters_writable fs/ocfs2/refcounttree.c:3255 [inline]\n    ocfs2_replace_cow+0x991/0x1660 fs/ocfs2/refcounttree.c:3349\n    ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3427 [inline]\n    ocfs2_refcount_cow+0x5e1/0x9f0 fs/ocfs2/refcounttree.c:3470\n    ocfs2_prepare_inode_for_write fs/ocfs2/file.c:2340 [inline]\n    ocfs2_file_write_iter+0xbda/0x1880 fs/ocfs2/file.c:2451\n    iter_file_splice_write+0x890/0xf60 fs/splice.c:743\n    do_splice_from fs/splice.c:9\n---truncated---\n\n## Affected\n\n- `Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 5ff30f07def6d0e6edacf47952807b5ff60f3af6`\n- `Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 2753e12853ed2023555cec2c5fe22fbaabb2c0b7`\n- `Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < f0261b3aca027f5c409a402ea22f6982750f911c`\n- `Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < a4adaa722977f46511d4247172cd4ec991b80ff2`\n- `Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 123c050eb96aae0bab74c9f06c6ad3de7992722b`\n- `Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 71f07b7f90b3109c9098d1b9c8efbbeece5deb8a`\n- `Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 09e93a60e18e83a630ff84ae00cb564bab96ab1f`\n- `Linux >= 6f70fa519976a379d72781d927cf8e5f5b05ec86 < 82ea9d4fc05fb7a387db547c6a7c0aa6a3719616`\n- `Linux 2.6.32`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89496.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":203937,"id":"CVE-2026-89496","ts":1789490229049,"field":"cvss","old":null,"new":"5.5"},{"seq":203936,"id":"CVE-2026-89496","ts":1789490229049,"field":"severity","old":"none","new":"medium"},{"seq":147075,"id":"CVE-2026-89496","ts":1789270195063,"field":"cvss","old":null,"new":"5.5"},{"seq":147074,"id":"CVE-2026-89496","ts":1789270195063,"field":"severity","old":"none","new":"medium"}]}