{"cve":"CVE-2024-26644","nvd":{"published":"2024-03-26T16:15:12.137","modified":"2026-06-17T07:17:59.353","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: don't abort filesystem when attempting to snapshot deleted subvolume\n\nIf the source file descriptor to the snapshot ioctl refers to a deleted\nsubvolume, we get the following abort:\n\n  BTRFS: Transaction aborted (error -2)\n  WARNING: CPU: 0 PID: 833 at fs/btrfs/transaction.c:1875 create_pending_snapshot+0x1040/0x1190 [btrfs]\n  Modules linked in: pata_acpi btrfs ata_piix libata scsi_mod virtio_net blake2b_generic xor net_failover virtio_rng failover scsi_common rng_core raid6_pq libcrc32c\n  CPU: 0 PID: 833 Comm: t_snapshot_dele Not tainted 6.7.0-rc6 #2\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-1.fc39 04/01/2014\n  RIP: 0010:create_pending_snapshot+0x1040/0x1190 [btrfs]\n  RSP: 0018:ffffa09c01337af8 EFLAGS: 00010282\n  RAX: 0000000000000000 RBX: ffff9982053e7c78 RCX: 0000000000000027\n  RDX: ffff99827dc20848 RSI: 0000000000000001 RDI: ffff99827dc20840\n  RBP: ffffa09c01337c00 R08: 0000000000000000 R09: ffffa09c01337998\n  R10: 0000000000000003 R11: ffffffffb96da248 R12: fffffffffffffffe\n  R13: ffff99820535bb28 R14: ffff99820b7bd000 R15: ffff99820381ea80\n  FS:  00007fe20aadabc0(0000) GS:ffff99827dc00000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 0000559a120b502f CR3: 00000000055b6000 CR4: 00000000000006f0\n  Call Trace:\n   <TASK>\n   ? create_pending_snapshot+0x1040/0x1190 [btrfs]\n   ? __warn+0x81/0x130\n   ? create_pending_snapshot+0x1040/0x1190 [btrfs]\n   ? report_bug+0x171/0x1a0\n   ? handle_bug+0x3a/0x70\n   ? exc_invalid_op+0x17/0x70\n   ? asm_exc_invalid_op+0x1a/0x20\n   ? create_pending_snapshot+0x1040/0x1190 [btrfs]\n   ? create_pending_snapshot+0x1040/0x1190 [btrfs]\n   create_pending_snapshots+0x92/0xc0 [btrfs]\n   btrfs_commit_transaction+0x66b/0xf40 [btrfs]\n   btrfs_mksubvol+0x301/0x4d0 [btrfs]\n   btrfs_mksnapshot+0x80/0xb0 [btrfs]\n   __btrfs_ioctl_snap_create+0x1c2/0x1d0 [btrfs]\n   btrfs_ioctl_snap_create_v2+0xc4/0x150 [btrfs]\n   btrfs_ioctl+0x8a6/0x2650 [btrfs]\n   ? kmem_cache_free+0x22/0x340\n   ? do_sys_openat2+0x97/0xe0\n   __x64_sys_ioctl+0x97/0xd0\n   do_syscall_64+0x46/0xf0\n   entry_SYSCALL_64_after_hwframe+0x6e/0x76\n  RIP: 0033:0x7fe20abe83af\n  RSP: 002b:00007ffe6eff1360 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\n  RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fe20abe83af\n  RDX: 00007ffe6eff23c0 RSI: 0000000050009417 RDI: 0000000000000003\n  RBP: 0000000000000003 R08: 0000000000000000 R09: 00007fe20ad16cd0\n  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\n  R13: 00007ffe6eff13c0 R14: 00007fe20ad45000 R15: 0000559a120b6d58\n   </TASK>\n  ---[ end trace 0000000000000000 ]---\n  BTRFS: error (device vdc: state A) in create_pending_snapshot:1875: errno=-2 No such entry\n  BTRFS info (device vdc: state EA): forced readonly\n  BTRFS warning (device vdc: state EA): Skipping commit of aborted transaction.\n  BTRFS: error (device vdc: state EA) in cleanup_transaction:2055: errno=-2 No such entry\n\nThis happens because create_pending_snapshot() initializes the new root\nitem as a copy of the source root item. This includes the refs field,\nwhich is 0 for a deleted subvolume. The call to btrfs_insert_root()\ntherefore inserts a root with refs == 0. btrfs_get_new_fs_root() then\nfinds the root and returns -ENOENT if refs == 0, which causes\ncreate_pending_snapshot() to abort.\n\nFix it by checking the source root's refs before attempting the\nsnapshot, but after locking subvol_sem to avoid racing with deletion.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-908"],"references":["https://git.kernel.org/stable/c/0877497dc97834728e1b528ddf1e1c484292c29c","https://git.kernel.org/stable/c/2bdf872bcfe629a6202ffd6641615a8ed00e8464","https://git.kernel.org/stable/c/6e6bca99e8d88d989a7cde4c064abea552d5219b","https://git.kernel.org/stable/c/7081929ab2572920e94d70be3d332e5c9f97095a","https://git.kernel.org/stable/c/c06941564027bdbc01d2df7f41e333c11cb0482d"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:47:51.568503435+00:00"},"epss":{"cve":"CVE-2024-26644","score":0.0023,"percentile":0.13947,"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."]}