CVE-2023-53692

Estado: AplazadaAlta (7.8)—

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

ext4: fix use-after-free read in ext4_find_extent for bigalloc + inline

Syzbot found the following issue: loop0: detected capacity change from 0 to 2048 EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: none. ================================================================== BUG: KASAN: use-after-free in ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline] BUG: KASAN: use-after-free in ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931 Read of size 4 at addr ffff888073644750 by task syz-executor420/5067

Leer descripción completaMostrar menos

Above issue is happens when enable bigalloc and inline data feature. As commit 131294c35ed6 fixed delayed allocation bug in ext4_clu_mapped for bigalloc + inline. But it only resolved issue when has inline data, if inline data has been converted to extent(ext4_da_convert_inline_data_to_extent) before writepages, there is no EXT4_STATE_MAY_INLINE_DATA flag. However i_data is still store inline data in this scene. Then will trigger UAF when find extent. To resolve above issue, there is need to add judge "ext4_has_inline_data(inode)" in ext4_clu_mapped().

Detalles técnicos trazas, registros y código del informe original

CPU: 0 PID: 5067 Comm: syz-executor420 Not tainted 6.2.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
 print_address_description+0x74/0x340 mm/kasan/report.c:306
 print_report+0x107/0x1f0 mm/kasan/report.c:417
 kasan_report+0xcd/0x100 mm/kasan/report.c:517
 ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]
 ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931
 ext4_clu_mapped+0x117/0x970 fs/ext4/extents.c:5809
 ext4_insert_delayed_block fs/ext4/inode.c:1696 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1806 [inline]
 ext4_da_get_block_prep+0x9e8/0x13c0 fs/ext4/inode.c:1870
 ext4_block_write_begin+0x6a8/0x2290 fs/ext4/inode.c:1098
 ext4_da_write_begin+0x539/0x760 fs/ext4/inode.c:3082
 generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772
 ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285
 ext4_file_write_iter+0x1d0/0x18f0
 call_write_iter include/linux/fs.h:2186 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7dc/0xc50 fs/read_write.c:584
 ksys_write+0x177/0x2a0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f4b7a9737b9
RSP: 002b:00007ffc5cac3668 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b7a9737b9
RDX: 00000000175d9003 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 00007f4b7a933050 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000079f R11: 0000000000000246 R12: 00007f4b7a9330e0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

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 secundarioT1005 Data from Local Systemcollection65 %

Vulnerabilidad local de use-after-free en ext4 que requiere acceso local (AV:L, PR:L) sin interacción del usuario. El defecto en ext4_find_extent permite lectura de memoria de kernel y potencial DoS al escribir datos. CVSS HIGH con confidencialidad e integridad completas.

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)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2023-53692",
  "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
      }
    ]
  },
  "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": "1ed1eef0551bebee8e56973ccd0900e3578edfb7",
              "lessThan": "0ce15000dee0ecd6f235f925a327803e2ef489c6",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6f4200ec76a0d31200c308ec5a71c68df5417004",
              "lessThan": "a34f6dcb78c654ab905642c1b4e7e5fbb4f0babe",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9404839e0c9db5a517ea83c0ca3388b39d105fdf",
              "lessThan": "770b0613637f59f3091dda1ff0c23671a5326b9c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d440d6427a5e3a877c1c259b8d2b216ddb65e185",
              "lessThan": "40566def189c513be2c694681256d7486cc6e368",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "81b915181c630ee1cffa052e52874fe4e1ba91ac",
              "lessThan": "96d440bee177669dc0acedca0abd73bae6a9be8b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "131294c35ed6f777bd4e79d42af13b5c41bf2775",
              "lessThan": "11c87c8df2cae1d6be83c07e59fef0792de73482",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "131294c35ed6f777bd4e79d42af13b5c41bf2775",
              "lessThan": "14da044725a3ab10affa3566d29c15737c0e67a4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "131294c35ed6f777bd4e79d42af13b5c41bf2775",
              "lessThan": "835659598c67907b98cd2aa57bb951dfaf675c69",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c0c8edbc8abbe8f16d80a1d794d1ba2c12b6f193",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4.19.270",
              "lessThan": "4.19.271",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "5.4.229",
              "lessThan": "5.4.243",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "5.10.163",
              "lessThan": "5.10.180",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "5.15.87",
              "lessThan": "5.15.111",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.1.4",
              "lessThan": "6.1.28",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.0.18",
              "lessThan": "6.1",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "fs/ext4/extents.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.2"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.2",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "4.19.271",
              "versionType": "semver",
              "lessThanOrEqual": "4.19.*"
            },
            {
              "status": "unaffected",
              "version": "5.4.243",
              "versionType": "semver",
              "lessThanOrEqual": "5.4.*"
            },
            {
              "status": "unaffected",
              "version": "5.10.180",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.111",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.28",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.2.15",
              "versionType": "semver",
              "lessThanOrEqual": "6.2.*"
            },
            {
              "status": "unaffected",
              "version": "6.3.2",
              "versionType": "semver",
              "lessThanOrEqual": "6.3.*"
            },
            {
              "status": "unaffected",
              "version": "6.4",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/ext4/extents.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-10-22T14:15:43.670",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0ce15000dee0ecd6f235f925a327803e2ef489c6",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/11c87c8df2cae1d6be83c07e59fef0792de73482",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/14da044725a3ab10affa3566d29c15737c0e67a4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/40566def189c513be2c694681256d7486cc6e368",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/770b0613637f59f3091dda1ff0c23671a5326b9c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/835659598c67907b98cd2aa57bb951dfaf675c69",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/96d440bee177669dc0acedca0abd73bae6a9be8b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a34f6dcb78c654ab905642c1b4e7e5fbb4f0babe",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix use-after-free read in ext4_find_extent for bigalloc + inline\n\nSyzbot found the following issue:\nloop0: detected capacity change from 0 to 2048\nEXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: none.\n==================================================================\nBUG: KASAN: use-after-free in ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]\nBUG: KASAN: use-after-free in ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931\nRead of size 4 at addr ffff888073644750 by task syz-executor420/5067\n\nCPU: 0 PID: 5067 Comm: syz-executor420 Not tainted 6.2.0-rc1-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106\n print_address_description+0x74/0x340 mm/kasan/report.c:306\n print_report+0x107/0x1f0 mm/kasan/report.c:417\n kasan_report+0xcd/0x100 mm/kasan/report.c:517\n ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]\n ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931\n ext4_clu_mapped+0x117/0x970 fs/ext4/extents.c:5809\n ext4_insert_delayed_block fs/ext4/inode.c:1696 [inline]\n ext4_da_map_blocks fs/ext4/inode.c:1806 [inline]\n ext4_da_get_block_prep+0x9e8/0x13c0 fs/ext4/inode.c:1870\n ext4_block_write_begin+0x6a8/0x2290 fs/ext4/inode.c:1098\n ext4_da_write_begin+0x539/0x760 fs/ext4/inode.c:3082\n generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772\n ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285\n ext4_file_write_iter+0x1d0/0x18f0\n call_write_iter include/linux/fs.h:2186 [inline]\n new_sync_write fs/read_write.c:491 [inline]\n vfs_write+0x7dc/0xc50 fs/read_write.c:584\n ksys_write+0x177/0x2a0 fs/read_write.c:637\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\nRIP: 0033:0x7f4b7a9737b9\nRSP: 002b:00007ffc5cac3668 EFLAGS: 00000246 ORIG_RAX: 0000000000000001\nRAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b7a9737b9\nRDX: 00000000175d9003 RSI: 0000000020000200 RDI: 0000000000000004\nRBP: 00007f4b7a933050 R08: 0000000000000000 R09: 0000000000000000\nR10: 000000000000079f R11: 0000000000000246 R12: 00007f4b7a9330e0\nR13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000\n </TASK>\n\nAbove issue is happens when enable bigalloc and inline data feature. As\ncommit 131294c35ed6 fixed delayed allocation bug in ext4_clu_mapped for\nbigalloc + inline. But it only resolved issue when has inline data, if\ninline data has been converted to extent(ext4_da_convert_inline_data_to_extent)\nbefore writepages, there is no EXT4_STATE_MAY_INLINE_DATA flag. However\ni_data is still store inline data in this scene. Then will trigger UAF\nwhen find extent.\nTo resolve above issue, there is need to add judge \"ext4_has_inline_data(inode)\"\nin ext4_clu_mapped()."
    }
  ],
  "lastModified": "2026-08-04T10:19:18.123",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}