btrfs: reject root items with drop_progress and zero drop_level

{
  "id": "a8d0c3f34b23c9d1764b709315fee207eae8324858c6cbe09f5f1611b0f5f45a",
  "url": "https://osv.dev/vulnerability/CVE-2026-43046",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "btrfs: reject root items with drop_progress and zero drop_level",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: btrfs: reject root items with drop_progress and zero drop_level [BUG] When recovering relocation at mount time, merge_reloc_root() and btrfs_drop_snapshot() both use BUG_ON(level == 0) to guard against an impossible state: a non-zero drop_progress combined with a zero drop_level in a root_item, which can be triggered: ------------[ cut here ]------------ kernel BUG at fs/btrfs/relocation.c:1545! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 1 UID: 0 PID: 283 ... Tainted: 6.18.0+ #16 PREEMPT(voluntary) Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: QEMU Ubuntu 24.04 PC v2, BIOS 1.16.3-debian-1.16.3-2 RIP: 0010:merge_reloc_root+0x1266/0x1650 fs/btrfs/relocation.c:1545 Code: ffff0000 00004589 d7e9acfa ffffe8a1 79bafebe 02000000 Call Trace: merge_reloc_roots+0x295/0x890 fs/btrfs/relocation.c:1861 btrfs_recover_relocation+0xd6e/0x11d0 fs/btrfs/relocation.c:4195 btrfs_start_pre_rw_mount+0xa4d/0x1810 fs/btrfs/disk-io.c:3130 open_ctree+0x5824/0x5fe0 fs/btrfs/disk-io.c:3640 btrfs_fill_super fs/btrfs/super.c:987 [inline] btrfs_get_tree_super fs/btrfs/super.c:1951 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2094 [inline] btrfs_get_tree+0x111c/0x2190 fs/btrfs/super.c:2128 vfs_get_tree+0x9a/0x370 fs/super.c:1758 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3642 [inline] do_new_mount fs/namespace.c:3718 [inline] path_mount+0x5b8/0x1ea0 fs/namespace.c:4028 do_mount fs/namespac",
    "evidence": "osv:CVE-2026-43046",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.203",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.168",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.134",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.81",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.22",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.12",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-43046",
      "aliases": [
        "CVE-2026-43046"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "9f3a742736cecda5a8778be70faa2f779458839f"
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                {
                  "fixed": "bedaf7d0b9d793e116f16b4d9a7dbc94bcc80443"
                },
                {
                  "fixed": "ac68a9a8e481ab1becaed29d6d23087dac3de15d"
                },
                {
                  "fixed": "295f8075d00442d71dc9ccae421ace1c0d2d9224"
                },
                {
                  "fixed": "53ceedd1eb6280ca8359664e0226983eded2ed73"
                },
                {
                  "fixed": "850de3d87f4720b71ccdcd44f4aa57e46b53a3f3"
                },
                {
                  "fixed": "de585ee18dd5601745f65a60fef7b7ceebd78c83"
                },
                {
                  "fixed": "b17b79ff896305fd74980a5f72afec370ee88ca4"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43046.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.29"
                },
                {
                  "fixed": "5.15.203"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.168"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.134"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.81"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.22"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "6.19.12"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43046.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.064635197Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/295f8075d00442d71dc9ccae421ace1c0d2d9224",
        "https://git.kernel.org/stable/c/53ceedd1eb6280ca8359664e0226983eded2ed73",
        "https://git.kernel.org/stable/c/850de3d87f4720b71ccdcd44f4aa57e46b53a3f3",
        "https://git.kernel.org/stable/c/ac68a9a8e481ab1becaed29d6d23087dac3de15d",
        "https://git.kernel.org/stable/c/b17b79ff896305fd74980a5f72afec370ee88ca4",
        "https://git.kernel.org/stable/c/bedaf7d0b9d793e116f16b4d9a7dbc94bcc80443",
        "https://git.kernel.org/stable/c/de585ee18dd5601745f65a60fef7b7ceebd78c83",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43046.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-43046",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43046.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-43046",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 505042,
  "published_at": "2026-05-01T14:15:41.849+00:00"
}