{"cve":"CVE-2026-46251","nvd":{"published":"2026-06-03T18:16:25.603","modified":"2026-06-17T10:53:24.967","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix block_group_tree dirty_list corruption\n\nWhen the incompat flag EXTENT_TREE_V2 is set, we unconditionally add the\nblock group tree to the switch_commits list before calling\nswitch_commit_roots, as we do for the tree root and the chunk root.\nHowever, the block group tree uses normal root dirty tracking and in any\ntransaction that does an allocation and dirties a block group, the block\ngroup root will already be linked to a list by the dirty_list field and\nthis use of list_add_tail() is invalid and corrupts the prev/next\nmembers of block_group_root->dirty_list.\n\nThis is apparent on a subsequent list_del on the prev if we enable\nCONFIG_DEBUG_LIST:\n\n  [32.1571] ------------[ cut here ]------------\n  [32.1572] list_del corruption. next->prev should beffff958890202538, but was ffff9588992bd538. (next=ffff958890201538)\n  [32.1575] WARNING: lib/list_debug.c:65 at 0x0, CPU#3: sync/607\n  [32.1583] CPU: 3 UID: 0 PID: 607 Comm: sync Not tainted 6.18.0 #24PREEMPT(none)\n  [32.1585] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS1.17.0-4.fc41 04/01/2014\n  [32.1587] RIP: 0010:__list_del_entry_valid_or_report+0x108/0x120\n  [32.1593] RSP: 0018:ffffaa288287fdd0 EFLAGS: 00010202\n  [32.1594] RAX: 0000000000000001 RBX: ffff95889326e800 RCX:ffff958890201538\n  [32.1596] RDX: ffff9588992bd538 RSI: ffff958890202538 RDI:ffffffff82a41e00\n  [32.1597] RBP: ffff958890202538 R08: ffffffff828fc1e8 R09:00000000ffffefff\n  [32.1599] R10: ffffffff8288c200 R11: ffffffff828e4200 R12:ffff958890201538\n  [32.1601] R13: ffff95889326e958 R14: ffff958895c24000 R15:ffff958890202538\n  [32.1603] FS:  00007f0c28eb5740(0000) GS:ffff958af2bd2000(0000)knlGS:0000000000000000\n  [32.1605] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  [32.1607] CR2: 00007f0c28e8a3cc CR3: 0000000109942005 CR4:0000000000370ef0\n  [32.1609] Call Trace:\n  [32.1610]  <TASK>\n  [32.1611]  switch_commit_roots+0x82/0x1d0 [btrfs]\n  [32.1615]  btrfs_commit_transaction+0x968/0x1550 [btrfs]\n  [32.1618]  ? btrfs_attach_transaction_barrier+0x23/0x60 [btrfs]\n  [32.1621]  __iterate_supers+0xe8/0x190\n  [32.1622]  ? __pfx_sync_fs_one_sb+0x10/0x10\n  [32.1623]  ksys_sync+0x63/0xb0\n  [32.1624]  __do_sys_sync+0xe/0x20\n  [32.1625]  do_syscall_64+0x73/0x450\n  [32.1626]  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n  [32.1627] RIP: 0033:0x7f0c28d05d2b\n  [32.1632] RSP: 002b:00007ffc9d988048 EFLAGS: 00000246 ORIG_RAX:00000000000000a2\n  [32.1634] RAX: ffffffffffffffda RBX: 00007ffc9d988228 RCX:00007f0c28d05d2b\n  [32.1636] RDX: 00007f0c28e02301 RSI: 00007ffc9d989b21 RDI:00007f0c28dba90d\n  [32.1637] RBP: 0000000000000001 R08: 0000000000000001 R09:0000000000000000\n  [32.1639] R10: 0000000000000000 R11: 0000000000000246 R12:000055b96572cb80\n  [32.1641] R13: 000055b96572b19f R14: 00007f0c28dfa434 R15:000055b96572b034\n  [32.1643]  </TASK>\n  [32.1644] irq event stamp: 0\n  [32.1644] hardirqs last  enabled at (0): [<0000000000000000>] 0x0\n  [32.1646] hardirqs last disabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260\n  [32.1648] softirqs last  enabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260\n  [32.1650] softirqs last disabled at (0): [<0000000000000000>] 0x0\n  [32.1652] ---[ end trace 0000000000000000 ]---\n\nFurthermore, this list corruption eventually (when we happen to add a\nnew block group) results in getting the switch_commits and\ndirty_cowonly_roots lists mixed up and attempting to call update_root\non the tree root which can't be found in the tree root, resulting in a\ntransaction abort:\n\n  [87.8269] BTRFS critical (device nvme1n1): unable to find root key (1 0 0) in tree 1\n  [87.8272] ------------[ cut here ]------------\n  [87.8274] BTRFS: Transaction aborted (error -117)\n  [87.8275] WARNING: fs/btrfs/root-tree.c:153 at 0x0, CPU#4: sync/703\n  [87.8285] CPU: 4 UID: 0 PID: 703 Comm: sync Not tainted 6.18.0 #25 PREEMPT(none)\n  [87.8287] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-4.fc41 0\n---truncated---","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.4},"cwes":[],"references":["https://git.kernel.org/stable/c/201091da34c4f113af6b4a7407091c39bf29d4ca","https://git.kernel.org/stable/c/3a1f4264daed4b419c325a7fe35e756cada3cf82","https://git.kernel.org/stable/c/4eb830847d84276f1c8ea46541cfeeedaba1fb63","https://git.kernel.org/stable/c/6e10283b5519d987d880d71bec90cdc7f2ec62b3","https://git.kernel.org/stable/c/80e1fda9c084dcf54819a12bc7682ec0afd2d8f4"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:37:48.043517290+00:00"},"epss":{"cve":"CVE-2026-46251","score":0.00132,"percentile":0.02752,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}