CVE-2023-53187

Estado: ModificadaAlta (7.8)—

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

btrfs: fix use-after-free of new block group that became unused

If a task creates a new block group and that block group becomes unused before we finish its creation, at btrfs_create_pending_block_groups(), then when btrfs_mark_bg_unused() is called against the block group, we assume that the block group is currently in the list of block groups to reclaim, and we move it out of the list of new block groups and into the list of unused block groups. This has two consequences:

This second case was caught when running generic/297 from fstests, which produced the following assertion failure and stack trace:

Detalles técnicos trazas, registros y código del informe original

1) We move it out of the list of new block groups associated to the
   current transaction. So the block group creation is not finished and
   if we attempt to delete the bg because it's unused, we will not find
   the block group item in the extent tree (or the new block group tree),
   its device extent items in the device tree etc, resulting in the
   deletion to fail due to the missing items;

2) We don't increment the reference count on the block group when we
   move it to the list of unused block groups, because we assumed the
   block group was on the list of block groups to reclaim, and in that
   case it already has the correct reference count. However the block
   group was on the list of new block groups, in which case no extra
   reference was taken because it's local to the current task. This
   later results in doing an extra reference count decrement when
   removing the block group from the unused list, eventually leading the
   reference count to 0.

  [589.559] assertion failed: refcount_read(&block_group->refs) == 1, in fs/btrfs/block-group.c:4299
  [589.559] ------------[ cut here ]------------
  [589.559] kernel BUG at fs/btrfs/block-group.c:4299!
  [589.560] invalid opcode: 0000 [#1] PREEMPT SMP PTI
  [589.560] CPU: 8 PID: 2819134 Comm: umount Tainted: G        W          6.4.0-rc6-btrfs-next-134+ #1
  [589.560] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
  [589.560] RIP: 0010:btrfs_free_block_groups+0x449/0x4a0 [btrfs]
  [589.561] Code: 68 62 da c0 (...)
  [589.561] RSP: 0018:ffffa55a8c3b3d98 EFLAGS: 00010246
  [589.561] RAX: 0000000000000058 RBX: ffff8f030d7f2000 RCX: 0000000000000000
  [589.562] RDX: 0000000000000000 RSI: ffffffff953f0878 RDI: 00000000ffffffff
  [589.562] RBP: ffff8f030d7f2088 R08: 0000000000000000 R09: ffffa55a8c3b3c50
  [589.562] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8f05850b4c00
  [589.562] R13: ffff8f030d7f2090 R14: ffff8f05850b4cd8 R15: dead000000000100
  [589.563] FS:  00007f497fd2e840(0000) GS:ffff8f09dfc00000(0000) knlGS:0000000000000000
  [589.563] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [589.563] CR2: 00007f497ff8ec10 CR3: 0000000271472006 CR4: 0000000000370ee0
  [589.563] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [589.564] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [589.564] Call Trace:
  [589.564]  <TASK>
  [589.565]  ? __die_body+0x1b/0x60
  [589.565]  ? die+0x39/0x60
  [589.565]  ? do_trap+0xeb/0x110
  [589.565]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
  [589.566]  ? do_error_trap+0x6a/0x90
  [589.566]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
  [589.566]  ? exc_invalid_op+0x4e/0x70
  [589.566]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
  [589.567]  ? asm_exc_invalid_op+0x16/0x20
  [589.567]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
  [589.567]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
  [589.567]  close_ctree+0x35d/0x560 [btrfs]
  [589.568]  ? fsnotify_sb_delete+0x13e/0x1d0
  [589.568]  ? dispose_list+0x3a/0x50
  [589.568]  ? evict_inodes+0x151/0x1a0
  [589.568]  generic_shutdown_super+0x73/0x1a0
  [589.569]  kill_anon_super+0x14/0x30
  [589.569]  btrfs_kill_super+0x12/0x20 [btrfs]
  [589.569]  deactivate_locked
---truncated---

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.16%
Percentil entre todas las CVEs puntuadas: 5
Fecha de la puntuación: 5/10/2026

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %
Impacto secundarioT1561.002 Disk Structure Wipeimpact65 %

CWE-416 (use-after-free) con AV:L/PR:L permite escalada de privilegios local. El defecto causa pánico del kernel (DoS) y potencial corrupción de datos en el sistema de archivos btrfs.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-416

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2023-53187",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      },
      {
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        "source": "nvd@nist.gov",
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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
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        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
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  "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": "01eca70ef8cf499d0cb6d1bbd691558e7792cf17",
              "lessThan": "6297644db23f77c02ae7961cc542d162629ae2c4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5d19abcffd8404078dfa7d7118cec357b5e7bc58",
              "lessThan": "7569c4294ba6ff9f194635b14876198f8a687c4a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a9f189716cf15913c453299d72f69c51a9b0f86b",
              "lessThan": "0657b20c5a76c938612f8409735a8830d257866e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "edf3b5aadb2515c808200b904baa5b70a727f0ac",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5.15.128",
              "lessThan": "5.16",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "fs/btrfs/block-group.c",
            "fs/btrfs/block-group.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/block-group.c",
            "fs/btrfs/block-group.h"
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2025-09-15T14:15:40.907",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0657b20c5a76c938612f8409735a8830d257866e",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6297644db23f77c02ae7961cc542d162629ae2c4",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7569c4294ba6ff9f194635b14876198f8a687c4a",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix use-after-free of new block group that became unused\n\nIf a task creates a new block group and that block group becomes unused\nbefore we finish its creation, at btrfs_create_pending_block_groups(),\nthen when btrfs_mark_bg_unused() is called against the block group, we\nassume that the block group is currently in the list of block groups to\nreclaim, and we move it out of the list of new block groups and into the\nlist of unused block groups. This has two consequences:\n\n1) We move it out of the list of new block groups associated to the\n   current transaction. So the block group creation is not finished and\n   if we attempt to delete the bg because it's unused, we will not find\n   the block group item in the extent tree (or the new block group tree),\n   its device extent items in the device tree etc, resulting in the\n   deletion to fail due to the missing items;\n\n2) We don't increment the reference count on the block group when we\n   move it to the list of unused block groups, because we assumed the\n   block group was on the list of block groups to reclaim, and in that\n   case it already has the correct reference count. However the block\n   group was on the list of new block groups, in which case no extra\n   reference was taken because it's local to the current task. This\n   later results in doing an extra reference count decrement when\n   removing the block group from the unused list, eventually leading the\n   reference count to 0.\n\nThis second case was caught when running generic/297 from fstests, which\nproduced the following assertion failure and stack trace:\n\n  [589.559] assertion failed: refcount_read(&block_group->refs) == 1, in fs/btrfs/block-group.c:4299\n  [589.559] ------------[ cut here ]------------\n  [589.559] kernel BUG at fs/btrfs/block-group.c:4299!\n  [589.560] invalid opcode: 0000 [#1] PREEMPT SMP PTI\n  [589.560] CPU: 8 PID: 2819134 Comm: umount Tainted: G        W          6.4.0-rc6-btrfs-next-134+ #1\n  [589.560] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014\n  [589.560] RIP: 0010:btrfs_free_block_groups+0x449/0x4a0 [btrfs]\n  [589.561] Code: 68 62 da c0 (...)\n  [589.561] RSP: 0018:ffffa55a8c3b3d98 EFLAGS: 00010246\n  [589.561] RAX: 0000000000000058 RBX: ffff8f030d7f2000 RCX: 0000000000000000\n  [589.562] RDX: 0000000000000000 RSI: ffffffff953f0878 RDI: 00000000ffffffff\n  [589.562] RBP: ffff8f030d7f2088 R08: 0000000000000000 R09: ffffa55a8c3b3c50\n  [589.562] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8f05850b4c00\n  [589.562] R13: ffff8f030d7f2090 R14: ffff8f05850b4cd8 R15: dead000000000100\n  [589.563] FS:  00007f497fd2e840(0000) GS:ffff8f09dfc00000(0000) knlGS:0000000000000000\n  [589.563] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  [589.563] CR2: 00007f497ff8ec10 CR3: 0000000271472006 CR4: 0000000000370ee0\n  [589.563] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  [589.564] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  [589.564] Call Trace:\n  [589.564]  <TASK>\n  [589.565]  ? __die_body+0x1b/0x60\n  [589.565]  ? die+0x39/0x60\n  [589.565]  ? do_trap+0xeb/0x110\n  [589.565]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]\n  [589.566]  ? do_error_trap+0x6a/0x90\n  [589.566]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]\n  [589.566]  ? exc_invalid_op+0x4e/0x70\n  [589.566]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]\n  [589.567]  ? asm_exc_invalid_op+0x16/0x20\n  [589.567]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]\n  [589.567]  ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]\n  [589.567]  close_ctree+0x35d/0x560 [btrfs]\n  [589.568]  ? fsnotify_sb_delete+0x13e/0x1d0\n  [589.568]  ? dispose_list+0x3a/0x50\n  [589.568]  ? evict_inodes+0x151/0x1a0\n  [589.568]  generic_shutdown_super+0x73/0x1a0\n  [589.569]  kill_anon_super+0x14/0x30\n  [589.569]  btrfs_kill_super+0x12/0x20 [btrfs]\n  [589.569]  deactivate_locked\n---truncated---"
    }
  ],
  "lastModified": "2026-08-04T10:18:57.110",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F22B9A69-E286-47B2-9428-20C5AB28617F",
              "versionEndExcluding": "5.16",
              "versionStartIncluding": "5.15.128"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.5:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0B3E6E4D-E24E-4630-B00C-8C9901C597B0"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.5:rc2:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E4A01A71-0F09-4DB2-A02F-7EFFBE27C98D"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}