{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-26944","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-02-19T14:20:24.197Z","datePublished":"2024-05-01T05:18:04.909Z","dateUpdated":"2026-08-05T11:28:29.917Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:28:29.917Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: zoned: fix use-after-free in do_zone_finish()\n\nShinichiro reported the following use-after-free triggered by the device\nreplace operation in fstests btrfs/070.\n\n BTRFS info (device nullb1): scrub: finished on devid 1 with status: 0\n ==================================================================\n BUG: KASAN: slab-use-after-free in do_zone_finish+0x91a/0xb90 [btrfs]\n Read of size 8 at addr ffff8881543c8060 by task btrfs-cleaner/3494007\n\n CPU: 0 PID: 3494007 Comm: btrfs-cleaner Tainted: G        W          6.8.0-rc5-kts #1\n Hardware name: Supermicro Super Server/X11SPi-TF, BIOS 3.3 02/21/2020\n Call Trace:\n  <TASK>\n  dump_stack_lvl+0x5b/0x90\n  print_report+0xcf/0x670\n  ? __virt_addr_valid+0x200/0x3e0\n  kasan_report+0xd8/0x110\n  ? do_zone_finish+0x91a/0xb90 [btrfs]\n  ? do_zone_finish+0x91a/0xb90 [btrfs]\n  do_zone_finish+0x91a/0xb90 [btrfs]\n  btrfs_delete_unused_bgs+0x5e1/0x1750 [btrfs]\n  ? __pfx_btrfs_delete_unused_bgs+0x10/0x10 [btrfs]\n  ? btrfs_put_root+0x2d/0x220 [btrfs]\n  ? btrfs_clean_one_deleted_snapshot+0x299/0x430 [btrfs]\n  cleaner_kthread+0x21e/0x380 [btrfs]\n  ? __pfx_cleaner_kthread+0x10/0x10 [btrfs]\n  kthread+0x2e3/0x3c0\n  ? __pfx_kthread+0x10/0x10\n  ret_from_fork+0x31/0x70\n  ? __pfx_kthread+0x10/0x10\n  ret_from_fork_asm+0x1b/0x30\n  </TASK>\n\n Allocated by task 3493983:\n  kasan_save_stack+0x33/0x60\n  kasan_save_track+0x14/0x30\n  __kasan_kmalloc+0xaa/0xb0\n  btrfs_alloc_device+0xb3/0x4e0 [btrfs]\n  device_list_add.constprop.0+0x993/0x1630 [btrfs]\n  btrfs_scan_one_device+0x219/0x3d0 [btrfs]\n  btrfs_control_ioctl+0x26e/0x310 [btrfs]\n  __x64_sys_ioctl+0x134/0x1b0\n  do_syscall_64+0x99/0x190\n  entry_SYSCALL_64_after_hwframe+0x6e/0x76\n\n Freed by task 3494056:\n  kasan_save_stack+0x33/0x60\n  kasan_save_track+0x14/0x30\n  kasan_save_free_info+0x3f/0x60\n  poison_slab_object+0x102/0x170\n  __kasan_slab_free+0x32/0x70\n  kfree+0x11b/0x320\n  btrfs_rm_dev_replace_free_srcdev+0xca/0x280 [btrfs]\n  btrfs_dev_replace_finishing+0xd7e/0x14f0 [btrfs]\n  btrfs_dev_replace_by_ioctl+0x1286/0x25a0 [btrfs]\n  btrfs_ioctl+0xb27/0x57d0 [btrfs]\n  __x64_sys_ioctl+0x134/0x1b0\n  do_syscall_64+0x99/0x190\n  entry_SYSCALL_64_after_hwframe+0x6e/0x76\n\n The buggy address belongs to the object at ffff8881543c8000\n  which belongs to the cache kmalloc-1k of size 1024\n The buggy address is located 96 bytes inside of\n  freed 1024-byte region [ffff8881543c8000, ffff8881543c8400)\n\n The buggy address belongs to the physical page:\n page:00000000fe2c1285 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1543c8\n head:00000000fe2c1285 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0\n flags: 0x17ffffc0000840(slab|head|node=0|zone=2|lastcpupid=0x1fffff)\n page_type: 0xffffffff()\n raw: 0017ffffc0000840 ffff888100042dc0 ffffea0019e8f200 dead000000000002\n raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000\n page dumped because: kasan: bad access detected\n\n Memory state around the buggy address:\n  ffff8881543c7f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  ffff8881543c7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n >ffff8881543c8000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n                                                        ^\n  ffff8881543c8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n  ffff8881543c8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n\nThis UAF happens because we're accessing stale zone information of a\nalready removed btrfs_device in do_zone_finish().\n\nThe sequence of events is as follows:\n\nbtrfs_dev_replace_start\n  btrfs_scrub_dev\n   btrfs_dev_replace_finishing\n    btrfs_dev_replace_update_device_in_mapping_tree <-- devices replaced\n    btrfs_rm_dev_replace_free_srcdev\n     btrfs_free_device                              <-- device freed\n\ncleaner_kthread\n btrfs_delete_unused_bgs\n  btrfs_zone_finish\n   do_zone_finish              <-- refers the freed device\n\nThe reason for this is that we're using a\n---truncated---"}],"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 ordinary local filesystem activity (writes, deletions, ordered-extent completion, unused-block-group cleanup) on a mounted zoned btrfs; there is no network-facing component.\nAC:L - Once a device replace has completed, `block_group->physical_map` holds a permanently dangling `btrfs_device` pointer, so triggering `do_zone_finish()` via ordinary file I/O is deterministic and requires winning no race; the reporter reproduced it with a stock fstests run (btrfs/070).\nPR:L - The attacker needs only write access to the mounted zoned btrfs to drive `btrfs_zone_finish_endio()`/`btrfs_delete_unused_bgs()` into the freed device, and can additionally groom the kmalloc-1k slab from unprivileged context; the CAP_SYS_ADMIN device replace that creates the dangling pointer is routine admin maintenance (the primary use case for zoned btrfs on SMR drives), not a privilege the attacker must hold.\nUI:N - After the stale pointer exists, the btrfs cleaner kthread and normal write-completion paths call `do_zone_finish()` automatically, and the attacker can force them with their own file operations without any victim action.\nS:U - The corruption is confined to kernel slab memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The freed 1KB `btrfs_device` and `btrfs_zoned_device_info` objects are read after free, and slab grooming lets the attacker control the reallocated contents, turning `device->zone_info`/`device->bdev` dereferences into an attacker-directed kernel read primitive.\nI:H - `do_zone_finish()` performs UAF writes — `zinfo->reserved_active_zones++`, `atomic_inc(&zone_info->active_zones_left)`, and `test_and_clear_bit(zno, zone_info->active_zones)` with pointer and index both taken from freed memory — giving a controllable write/bit-clear primitive usable for control-flow hijacking, plus zone-management commands issued through a dangling `bdev`.\nA:H - The bug is a KASAN-confirmed slab use-after-free in the btrfs cleaner kthread that reliably oopses or panics the kernel, and it also drives blkdev_zone_mgmt() with freed block-device state."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/btrfs/zoned.c"],"versions":[{"version":"4dcbb8ab31c1292aea6a3f240e19523f633320c2","lessThan":"34ca809e055eca5cfe63d9c7efbf80b7c21b4e57","status":"affected","versionType":"git"},{"version":"4dcbb8ab31c1292aea6a3f240e19523f633320c2","lessThan":"1ec17ef59168a1a6f1105f5dc517f783839a5302","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/btrfs/zoned.c"],"versions":[{"version":"5.18","status":"affected"},{"version":"0","lessThan":"5.18","status":"unaffected","versionType":"semver"},{"version":"6.8.3","lessThanOrEqual":"6.8.*","status":"unaffected","versionType":"semver"},{"version":"6.9","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":"5.18","versionEndExcluding":"6.8.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.9"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/34ca809e055eca5cfe63d9c7efbf80b7c21b4e57"},{"url":"https://git.kernel.org/stable/c/1ec17ef59168a1a6f1105f5dc517f783839a5302"}],"title":"btrfs: zoned: fix use-after-free in do_zone_finish()","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2024-26944","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-05-28T17:52:17.817601Z"}}}],"providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2024-06-04T17:49:14.503Z"}},{"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2024-08-02T00:21:05.525Z"},"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/34ca809e055eca5cfe63d9c7efbf80b7c21b4e57","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/1ec17ef59168a1a6f1105f5dc517f783839a5302","tags":["x_transferred"]}]}]}}