CVE-2022-49170

Estado: ModificadaAlta (7.8)—

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

f2fs: fix to do sanity check on curseg->alloc_type

As Wenqing Liu reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=215657

- Reproduce tested on kernel 5.17-rc4, 5.17-rc6

1. mkdir test_crash 2. cd test_crash 3. unzip tmp2.zip 4. mkdir mnt 5. ./single_test.sh f2fs 2

The root cause is we missed to do sanity check on curseg->alloc_type, result in out-of-bound accessing on sbi->block_count[] array, fix it.

Detalles técnicos trazas, registros y código del informe original

- Overview
UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 when mount and operate a corrupted image

- Kernel dump
[   46.434454] loop0: detected capacity change from 0 to 131072
[   46.529839] F2FS-fs (loop0): Mounted with checkpoint version = 7548c2d9
[   46.738319] ================================================================================
[   46.738412] UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2
[   46.738475] index 231 is out of range for type 'unsigned int [2]'
[   46.738539] CPU: 2 PID: 939 Comm: umount Not tainted 5.17.0-rc6 #1
[   46.738547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[   46.738551] Call Trace:
[   46.738556]  <TASK>
[   46.738563]  dump_stack_lvl+0x47/0x5c
[   46.738581]  ubsan_epilogue+0x5/0x50
[   46.738592]  __ubsan_handle_out_of_bounds+0x68/0x80
[   46.738604]  f2fs_allocate_data_block+0xdff/0xe60 [f2fs]
[   46.738819]  do_write_page+0xef/0x210 [f2fs]
[   46.738934]  f2fs_do_write_node_page+0x3f/0x80 [f2fs]
[   46.739038]  __write_node_page+0x2b7/0x920 [f2fs]
[   46.739162]  f2fs_sync_node_pages+0x943/0xb00 [f2fs]
[   46.739293]  f2fs_write_checkpoint+0x7bb/0x1030 [f2fs]
[   46.739405]  kill_f2fs_super+0x125/0x150 [f2fs]
[   46.739507]  deactivate_locked_super+0x60/0xc0
[   46.739517]  deactivate_super+0x70/0xb0
[   46.739524]  cleanup_mnt+0x11a/0x200
[   46.739532]  __cleanup_mnt+0x16/0x20
[   46.739538]  task_work_run+0x67/0xa0
[   46.739547]  exit_to_user_mode_prepare+0x18c/0x1a0
[   46.739559]  syscall_exit_to_user_mode+0x26/0x40
[   46.739568]  do_syscall_64+0x46/0xb0
[   46.739584]  entry_SYSCALL_64_after_hwframe+0x44/0xae

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: 0.27%
Percentil entre todas las CVEs puntuadas: 18
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 secundarioT1565.001 Stored Data Manipulationimpact60 %

Vector CVSS AV:L/PR:L/UI:N indica escalada local sin interacción (T1068). Acceso sin sanidad a array provoca DoS (corrupción de datos del kernel f2fs) o manipulación de estructura de archivos.

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 Restrict File and Directory Permissions Remote Data Storage Filter Network Traffic Execution Prevention Encrypt Sensitive Information

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-129

Referencias

JSON original (NVD)

Mostrar

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  "id": "CVE-2022-49170",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "nvd@nist.gov",
      "description": [
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          "lang": "en",
          "value": "CWE-129"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to do sanity check on curseg->alloc_type\n\nAs Wenqing Liu reported in bugzilla:\n\nhttps://bugzilla.kernel.org/show_bug.cgi?id=215657\n\n- Overview\nUBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 when mount and operate a corrupted image\n\n- Reproduce\ntested on kernel 5.17-rc4, 5.17-rc6\n\n1. mkdir test_crash\n2. cd test_crash\n3. unzip tmp2.zip\n4. mkdir mnt\n5. ./single_test.sh f2fs 2\n\n- Kernel dump\n[   46.434454] loop0: detected capacity change from 0 to 131072\n[   46.529839] F2FS-fs (loop0): Mounted with checkpoint version = 7548c2d9\n[   46.738319] ================================================================================\n[   46.738412] UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2\n[   46.738475] index 231 is out of range for type 'unsigned int [2]'\n[   46.738539] CPU: 2 PID: 939 Comm: umount Not tainted 5.17.0-rc6 #1\n[   46.738547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014\n[   46.738551] Call Trace:\n[   46.738556]  <TASK>\n[   46.738563]  dump_stack_lvl+0x47/0x5c\n[   46.738581]  ubsan_epilogue+0x5/0x50\n[   46.738592]  __ubsan_handle_out_of_bounds+0x68/0x80\n[   46.738604]  f2fs_allocate_data_block+0xdff/0xe60 [f2fs]\n[   46.738819]  do_write_page+0xef/0x210 [f2fs]\n[   46.738934]  f2fs_do_write_node_page+0x3f/0x80 [f2fs]\n[   46.739038]  __write_node_page+0x2b7/0x920 [f2fs]\n[   46.739162]  f2fs_sync_node_pages+0x943/0xb00 [f2fs]\n[   46.739293]  f2fs_write_checkpoint+0x7bb/0x1030 [f2fs]\n[   46.739405]  kill_f2fs_super+0x125/0x150 [f2fs]\n[   46.739507]  deactivate_locked_super+0x60/0xc0\n[   46.739517]  deactivate_super+0x70/0xb0\n[   46.739524]  cleanup_mnt+0x11a/0x200\n[   46.739532]  __cleanup_mnt+0x16/0x20\n[   46.739538]  task_work_run+0x67/0xa0\n[   46.739547]  exit_to_user_mode_prepare+0x18c/0x1a0\n[   46.739559]  syscall_exit_to_user_mode+0x26/0x40\n[   46.739568]  do_syscall_64+0x46/0xb0\n[   46.739584]  entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nThe root cause is we missed to do sanity check on curseg->alloc_type,\nresult in out-of-bound accessing on sbi->block_count[] array, fix it."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: f2fs: corrección para realizar una comprobación de cordura en curseg-&gt;alloc_type Como informó Wenqing Liu en bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215657 - Descripción general UBSAN: array-index-out-of-bounds en fs/f2fs/segment.c:3460:2 cuando se monta y opera una imagen dañada - Reproducir probado en kernel 5.17-rc4, 5.17-rc6 1. mkdir test_crash 2. cd test_crash 3. unzip tmp2.zip 4. mkdir mnt 5. ./single_test.sh f2fs 2 - Volcado de kernel [ 46.434454] loop0: se detectó un cambio de capacidad de 0 a 131072 [ 46.529839] F2FS-fs (loop0): montado con la versión de punto de control = 7548c2d9 [ 46.738319] ===================================================================================== [ 46.738412] UBSAN: índice de matriz fuera de los límites en fs/f2fs/segment.c:3460:2 [ 46.738475] el índice 231 está fuera de rango para el tipo 'unsigned int [2]' [ 46.738539] CPU: 2 PID: 939 Comm: umount No contaminado 5.17.0-rc6 #1 [ [46.738547] Nombre del hardware: PC estándar QEMU (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 01/04/2014 [ 46.738551] Seguimiento de llamadas: [ 46.738556]  [ 46.738563] dump_stack_lvl+0x47/0x5c [ 46.738581] ubsan_epilogue+0x5/0x50 [ 46.738592] __ubsan_handle_out_of_bounds+0x68/0x80 [ 46.738604] f2fs_allocate_data_block+0xdff/0xe60 [f2fs] [ 46.738819] do_write_page+0xef/0x210 [f2fs] [ 46.738934] f2fs_do_write_node_page+0x3f/0x80 [f2fs] [ 46.739038] __write_node_page+0x2b7/0x920 [f2fs] [ 46.739162] f2fs_sync_node_pages+0x943/0xb00 [f2fs] [ 46.739293] f2fs_write_checkpoint+0x7bb/0x1030 [f2fs] [ 46.739405] kill_f2fs_super+0x125/0x150 [f2fs] [ 46.739507] deactivate_locked_super+0x60/0xc0 [ 46.739517] deactivate_super+0x70/0xb0 [ 46.739524] cleanup_mnt+0x11a/0x200 [ 46.739532] __cleanup_mnt+0x16/0x20 [ 46.739538] task_work_run+0x67/0xa0 [ 46.739547] exit_to_user_mode_prepare+0x18c/0x1a0 [ 46.739559] syscall_exit_to_user_mode+0x26/0x40 [ 46.739568] do_syscall_64+0x46/0xb0 [ 46.739584] entry_SYSCALL_64_after_hwframe+0x44/0xae La causa raíz es que olvidamos realizar una verificación de integridad en curseg-&gt;alloc_type, lo que da como resultado un acceso fuera de los límites en la matriz sbi-&gt;block_count[], corríjalo."
    }
  ],
  "lastModified": "2026-08-13T00:17:30.040",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "25732027-6262-4C2F-8172-ACB077C6A9A0",
              "versionEndExcluding": "5.10.110",
              "versionStartIncluding": "3.8"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              "matchCriteriaId": "27C42AE8-B387-43E2-938A-E1C8B40BE6D5",
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            {
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              "vulnerable": true,
              "matchCriteriaId": "20C43679-0439-405A-B97F-685BEE50613B",
              "versionEndExcluding": "5.16.19",
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          "operator": "OR"
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}