{"id":"CVE-2026-89496","summary":"ocfs2: always run deallocs on copy-on-write completion","details":"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 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---","modified":"2026-09-13T03:47:18.714294380Z","published":"2026-09-11T19:43:46.772Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89496.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/09e93a60e18e83a630ff84ae00cb564bab96ab1f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/123c050eb96aae0bab74c9f06c6ad3de7992722b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/71f07b7f90b3109c9098d1b9c8efbbeece5deb8a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/82ea9d4fc05fb7a387db547c6a7c0aa6a3719616"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89496.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89496"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6f70fa519976a379d72781d927cf8e5f5b05ec86"},{"fixed":"123c050eb96aae0bab74c9f06c6ad3de7992722b"},{"fixed":"71f07b7f90b3109c9098d1b9c8efbbeece5deb8a"},{"fixed":"09e93a60e18e83a630ff84ae00cb564bab96ab1f"},{"fixed":"82ea9d4fc05fb7a387db547c6a7c0aa6a3719616"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89496.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.32"},{"fixed":"6.12.109"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.50"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89496.json"}}],"schema_version":"1.9.0"}