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CVE-2026-45934

Estado: En análisisMedia (5.5)—

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation

I have been observing a number of systems aborting at insert_dev_extents() in btrfs_create_pending_block_groups(). The following is a sample stack trace of such an abort coming from forced chunk allocation (typically behind CONFIG_BTRFS_EXPERIMENTAL) but this can theoretically happen to any DUP chunk allocation.

Inspecting these aborts with drgn, I observed a pattern of overlapping chunk_maps. Note how stripe 1 of the first chunk overlaps in physical address with stripe 0 of the second chunk.

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Physical Start Physical End Length Logical Type Stripe ---------------------------------------------------------------------------------------------------- 0x0000000102500000 0x0000000142500000 1.0G 0x0000000641d00000 META|DUP 0/2 0x0000000142500000 0x0000000182500000 1.0G 0x0000000641d00000 META|DUP 1/2 0x0000000142500000 0x0000000182500000 1.0G 0x0000000601d00000 META|DUP 0/2 0x0000000182500000 0x00000001c2500000 1.0G 0x0000000601d00000 META|DUP 1/2

Now how could this possibly happen? All chunk allocation is ---truncated---

Detalles técnicos trazas, registros y código del informe original
  [81.801] ------------[ cut here ]------------
  [81.801] BTRFS: Transaction aborted (error -17)
  [81.801] WARNING: fs/btrfs/block-group.c:2876 at btrfs_create_pending_block_groups+0x721/0x770 [btrfs], CPU#1: bash/319
  [81.802] Modules linked in: virtio_net btrfs xor zstd_compress raid6_pq null_blk
  [81.803] CPU: 1 UID: 0 PID: 319 Comm: bash Kdump: loaded Not tainted 6.19.0-rc6+ #319 NONE
  [81.803] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014
  [81.804] RIP: 0010:btrfs_create_pending_block_groups+0x723/0x770 [btrfs]
  [81.806] RSP: 0018:ffffa36241a6bce8 EFLAGS: 00010282
  [81.806] RAX: 000000000000000d RBX: ffff8e699921e400 RCX: 0000000000000000
  [81.807] RDX: 0000000002040001 RSI: 00000000ffffffef RDI: ffffffffc0608bf0
  [81.807] RBP: 00000000ffffffef R08: ffff8e69830f6000 R09: 0000000000000007
  [81.808] R10: ffff8e699921e5e8 R11: 0000000000000000 R12: ffff8e6999228000
  [81.808] R13: ffff8e6984d82000 R14: ffff8e69966a69c0 R15: ffff8e69aa47b000
  [81.809] FS:  00007fec6bdd9740(0000) GS:ffff8e6b1b379000(0000) knlGS:0000000000000000
  [81.809] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [81.810] CR2: 00005604833670f0 CR3: 0000000116679000 CR4: 00000000000006f0
  [81.810] Call Trace:
  [81.810]  <TASK>
  [81.810]  __btrfs_end_transaction+0x3e/0x2b0 [btrfs]
  [81.811]  btrfs_force_chunk_alloc_store+0xcd/0x140 [btrfs]
  [81.811]  kernfs_fop_write_iter+0x15f/0x240
  [81.812]  vfs_write+0x264/0x500
  [81.812]  ksys_write+0x6c/0xe0
  [81.812]  do_syscall_64+0x66/0x770
  [81.812]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  [81.813] RIP: 0033:0x7fec6be66197
  [81.814] RSP: 002b:00007fffb159dd30 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
  [81.815] RAX: ffffffffffffffda RBX: 00007fec6bdd9740 RCX: 00007fec6be66197
  [81.815] RDX: 0000000000000002 RSI: 0000560483374f80 RDI: 0000000000000001
  [81.816] RBP: 0000560483374f80 R08: 0000000000000000 R09: 0000000000000000
  [81.816] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002
  [81.817] R13: 00007fec6bfb85c0 R14: 00007fec6bfb5ee0 R15: 00005604833729c0
  [81.817]  </TASK>
  [81.817] irq event stamp: 20039
  [81.818] hardirqs last  enabled at (20047): [<ffffffff99a68302>] __up_console_sem+0x52/0x60
  [81.818] hardirqs last disabled at (20056): [<ffffffff99a682e7>] __up_console_sem+0x37/0x60
  [81.819] softirqs last  enabled at (19470): [<ffffffff999d2b46>] __irq_exit_rcu+0x96/0xc0
  [81.819] softirqs last disabled at (19463): [<ffffffff999d2b46>] __irq_exit_rcu+0x96/0xc0
  [81.820] ---[ end trace 0000000000000000 ]---
  [81.820] BTRFS: error (device dm-7 state A) in btrfs_create_pending_block_groups:2876: errno=-17 Object already exists

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-45934",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "1b9845081633072c18f30d8cfd09c267adf0b109",
              "lessThan": "7d4eadee7042d27fcea659fcdd738f463a7d2e70",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1b9845081633072c18f30d8cfd09c267adf0b109",
              "lessThan": "156cac365e27a82b64ae510c5f463fd81f0265b1",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1b9845081633072c18f30d8cfd09c267adf0b109",
              "lessThan": "b14c5e04bd0f722ed631845599d52d03fcae1bc1",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/btrfs/volumes.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.1"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.1",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.18.14",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/btrfs/volumes.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-05-27T14:17:09.480",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/156cac365e27a82b64ae510c5f463fd81f0265b1",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7d4eadee7042d27fcea659fcdd738f463a7d2e70",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b14c5e04bd0f722ed631845599d52d03fcae1bc1",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation\n\nI have been observing a number of systems aborting at\ninsert_dev_extents() in btrfs_create_pending_block_groups(). The\nfollowing is a sample stack trace of such an abort coming from forced\nchunk allocation (typically behind CONFIG_BTRFS_EXPERIMENTAL) but this\ncan theoretically happen to any DUP chunk allocation.\n\n  [81.801] ------------[ cut here ]------------\n  [81.801] BTRFS: Transaction aborted (error -17)\n  [81.801] WARNING: fs/btrfs/block-group.c:2876 at btrfs_create_pending_block_groups+0x721/0x770 [btrfs], CPU#1: bash/319\n  [81.802] Modules linked in: virtio_net btrfs xor zstd_compress raid6_pq null_blk\n  [81.803] CPU: 1 UID: 0 PID: 319 Comm: bash Kdump: loaded Not tainted 6.19.0-rc6+ #319 NONE\n  [81.803] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014\n  [81.804] RIP: 0010:btrfs_create_pending_block_groups+0x723/0x770 [btrfs]\n  [81.806] RSP: 0018:ffffa36241a6bce8 EFLAGS: 00010282\n  [81.806] RAX: 000000000000000d RBX: ffff8e699921e400 RCX: 0000000000000000\n  [81.807] RDX: 0000000002040001 RSI: 00000000ffffffef RDI: ffffffffc0608bf0\n  [81.807] RBP: 00000000ffffffef R08: ffff8e69830f6000 R09: 0000000000000007\n  [81.808] R10: ffff8e699921e5e8 R11: 0000000000000000 R12: ffff8e6999228000\n  [81.808] R13: ffff8e6984d82000 R14: ffff8e69966a69c0 R15: ffff8e69aa47b000\n  [81.809] FS:  00007fec6bdd9740(0000) GS:ffff8e6b1b379000(0000) knlGS:0000000000000000\n  [81.809] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  [81.810] CR2: 00005604833670f0 CR3: 0000000116679000 CR4: 00000000000006f0\n  [81.810] Call Trace:\n  [81.810]  <TASK>\n  [81.810]  __btrfs_end_transaction+0x3e/0x2b0 [btrfs]\n  [81.811]  btrfs_force_chunk_alloc_store+0xcd/0x140 [btrfs]\n  [81.811]  kernfs_fop_write_iter+0x15f/0x240\n  [81.812]  vfs_write+0x264/0x500\n  [81.812]  ksys_write+0x6c/0xe0\n  [81.812]  do_syscall_64+0x66/0x770\n  [81.812]  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n  [81.813] RIP: 0033:0x7fec6be66197\n  [81.814] RSP: 002b:00007fffb159dd30 EFLAGS: 00000202 ORIG_RAX: 0000000000000001\n  [81.815] RAX: ffffffffffffffda RBX: 00007fec6bdd9740 RCX: 00007fec6be66197\n  [81.815] RDX: 0000000000000002 RSI: 0000560483374f80 RDI: 0000000000000001\n  [81.816] RBP: 0000560483374f80 R08: 0000000000000000 R09: 0000000000000000\n  [81.816] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002\n  [81.817] R13: 00007fec6bfb85c0 R14: 00007fec6bfb5ee0 R15: 00005604833729c0\n  [81.817]  </TASK>\n  [81.817] irq event stamp: 20039\n  [81.818] hardirqs last  enabled at (20047): [<ffffffff99a68302>] __up_console_sem+0x52/0x60\n  [81.818] hardirqs last disabled at (20056): [<ffffffff99a682e7>] __up_console_sem+0x37/0x60\n  [81.819] softirqs last  enabled at (19470): [<ffffffff999d2b46>] __irq_exit_rcu+0x96/0xc0\n  [81.819] softirqs last disabled at (19463): [<ffffffff999d2b46>] __irq_exit_rcu+0x96/0xc0\n  [81.820] ---[ end trace 0000000000000000 ]---\n  [81.820] BTRFS: error (device dm-7 state A) in btrfs_create_pending_block_groups:2876: errno=-17 Object already exists\n\nInspecting these aborts with drgn, I observed a pattern of overlapping\nchunk_maps. Note how stripe 1 of the first chunk overlaps in physical\naddress with stripe 0 of the second chunk.\n\nPhysical Start     Physical End       Length       Logical            Type                 Stripe\n----------------------------------------------------------------------------------------------------\n0x0000000102500000 0x0000000142500000 1.0G         0x0000000641d00000 META|DUP             0/2\n0x0000000142500000 0x0000000182500000 1.0G         0x0000000641d00000 META|DUP             1/2\n0x0000000142500000 0x0000000182500000 1.0G         0x0000000601d00000 META|DUP             0/2\n0x0000000182500000 0x00000001c2500000 1.0G         0x0000000601d00000 META|DUP             1/2\n\nNow how could this possibly happen? All chunk allocation is\n---truncated---"
    }
  ],
  "lastModified": "2026-06-24T17:11:04.903",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "CEDF54D6-2C51-471F-814B-8D7AED5DAE54",
              "versionEndExcluding": "6.18.14",
              "versionStartIncluding": "4.1.1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "672A3E79-EC03-479D-8503-361DFBDC8092",
              "versionEndExcluding": "6.19.4",
              "versionStartIncluding": "6.19"
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              "criteria": "cpe:2.3:o:linux:linux_kernel:4.1:-:*:*:*:*:*:*",
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}