CVE-2022-50546

Estado: AnalizadaAlta (7.8)—

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

ext4: fix uninititialized value in 'ext4_evict_inode'

Now, 'ext4_alloc_inode()' didn't init 'ei->i_flags'. If new inode failed before set 'ei->i_flags' in '__ext4_new_inode()', then do 'iput()'. As after 6bc0d63dad7f commit will access 'ei->i_flags' in 'ext4_evict_inode()' which will lead to access uninit-value. To solve above issue just init 'ei->i_flags' in 'ext4_alloc_inode()'.

Detalles técnicos trazas, registros y código del informe original

Syzbot found the following issue:
=====================================================
BUG: KMSAN: uninit-value in ext4_evict_inode+0xdd/0x26b0 fs/ext4/inode.c:180
 ext4_evict_inode+0xdd/0x26b0 fs/ext4/inode.c:180
 evict+0x365/0x9a0 fs/inode.c:664
 iput_final fs/inode.c:1747 [inline]
 iput+0x985/0xdd0 fs/inode.c:1773
 __ext4_new_inode+0xe54/0x7ec0 fs/ext4/ialloc.c:1361
 ext4_mknod+0x376/0x840 fs/ext4/namei.c:2844
 vfs_mknod+0x79d/0x830 fs/namei.c:3914
 do_mknodat+0x47d/0xaa0
 __do_sys_mknodat fs/namei.c:3992 [inline]
 __se_sys_mknodat fs/namei.c:3989 [inline]
 __ia32_sys_mknodat+0xeb/0x150 fs/namei.c:3989
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Uninit was created at:
 __alloc_pages+0x9f1/0xe80 mm/page_alloc.c:5578
 alloc_pages+0xaae/0xd80 mm/mempolicy.c:2285
 alloc_slab_page mm/slub.c:1794 [inline]
 allocate_slab+0x1b5/0x1010 mm/slub.c:1939
 new_slab mm/slub.c:1992 [inline]
 ___slab_alloc+0x10c3/0x2d60 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc_lru+0x6f3/0xb30 mm/slub.c:3429
 alloc_inode_sb include/linux/fs.h:3117 [inline]
 ext4_alloc_inode+0x5f/0x860 fs/ext4/super.c:1321
 alloc_inode+0x83/0x440 fs/inode.c:259
 new_inode_pseudo fs/inode.c:1018 [inline]
 new_inode+0x3b/0x430 fs/inode.c:1046
 __ext4_new_inode+0x2a7/0x7ec0 fs/ext4/ialloc.c:959
 ext4_mkdir+0x4d5/0x1560 fs/ext4/namei.c:2992
 vfs_mkdir+0x62a/0x870 fs/namei.c:4035
 do_mkdirat+0x466/0x7b0 fs/namei.c:4060
 __do_sys_mkdirat fs/namei.c:4075 [inline]
 __se_sys_mkdirat fs/namei.c:4073 [inline]
 __ia32_sys_mkdirat+0xc4/0x120 fs/namei.c:4073
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

CPU: 1 PID: 4625 Comm: syz-executor.2 Not tainted 6.1.0-rc4-syzkaller-62821-gcb231e2f67ec #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
=====================================================

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: 0.21%
Percentil entre todas las CVEs puntuadas: 11
Fecha de la puntuación: 6/10/2026

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 escalation75 %
Impacto principalT1499.004 Application or System Exploitationimpact60 %

Vulnerabilidad local (AV:L/PR:L) en ext4 que causa lectura de memoria no inicializada. Un atacante local puede provocar DoS mediante uso malicioso de syscalls (mknod/mkdir) explotando el valor no inicializado en ei->i_flags durante evict_inode.

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-908

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2022-50546",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "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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      "affectedData": [
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              "lessThan": "5.10.164",
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              "version": "5.19.2",
              "lessThan": "5.20",
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          ],
          "programFiles": [
            "fs/ext4/super.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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              "status": "affected",
              "version": "6.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.164",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.87",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.0.18",
              "versionType": "semver",
              "lessThanOrEqual": "6.0.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.4",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/ext4/super.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-10-07T16:15:39.147",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/091f85db4c3fb1734a6d7fb4777a2b2831da6631",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3c31d8d3ad95aef8cc17a4fcf317e46217148439",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/56491d60ddca9c697d885394cb0173675b9ab81f",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7ea71af94eaaaf6d9aed24bc94a05b977a741cb9",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9f966e021c20caae639dd0e404c8761e8281a2c4",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e431b4fb1fb8c2654b808086e9747a000adb9655",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f0bffdcc7cb14598af2aa706f1e0f2a9054154ba",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-908"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix uninititialized value in 'ext4_evict_inode'\n\nSyzbot found the following issue:\n=====================================================\nBUG: KMSAN: uninit-value in ext4_evict_inode+0xdd/0x26b0 fs/ext4/inode.c:180\n ext4_evict_inode+0xdd/0x26b0 fs/ext4/inode.c:180\n evict+0x365/0x9a0 fs/inode.c:664\n iput_final fs/inode.c:1747 [inline]\n iput+0x985/0xdd0 fs/inode.c:1773\n __ext4_new_inode+0xe54/0x7ec0 fs/ext4/ialloc.c:1361\n ext4_mknod+0x376/0x840 fs/ext4/namei.c:2844\n vfs_mknod+0x79d/0x830 fs/namei.c:3914\n do_mknodat+0x47d/0xaa0\n __do_sys_mknodat fs/namei.c:3992 [inline]\n __se_sys_mknodat fs/namei.c:3989 [inline]\n __ia32_sys_mknodat+0xeb/0x150 fs/namei.c:3989\n do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]\n __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178\n do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203\n do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246\n entry_SYSENTER_compat_after_hwframe+0x70/0x82\n\nUninit was created at:\n __alloc_pages+0x9f1/0xe80 mm/page_alloc.c:5578\n alloc_pages+0xaae/0xd80 mm/mempolicy.c:2285\n alloc_slab_page mm/slub.c:1794 [inline]\n allocate_slab+0x1b5/0x1010 mm/slub.c:1939\n new_slab mm/slub.c:1992 [inline]\n ___slab_alloc+0x10c3/0x2d60 mm/slub.c:3180\n __slab_alloc mm/slub.c:3279 [inline]\n slab_alloc_node mm/slub.c:3364 [inline]\n slab_alloc mm/slub.c:3406 [inline]\n __kmem_cache_alloc_lru mm/slub.c:3413 [inline]\n kmem_cache_alloc_lru+0x6f3/0xb30 mm/slub.c:3429\n alloc_inode_sb include/linux/fs.h:3117 [inline]\n ext4_alloc_inode+0x5f/0x860 fs/ext4/super.c:1321\n alloc_inode+0x83/0x440 fs/inode.c:259\n new_inode_pseudo fs/inode.c:1018 [inline]\n new_inode+0x3b/0x430 fs/inode.c:1046\n __ext4_new_inode+0x2a7/0x7ec0 fs/ext4/ialloc.c:959\n ext4_mkdir+0x4d5/0x1560 fs/ext4/namei.c:2992\n vfs_mkdir+0x62a/0x870 fs/namei.c:4035\n do_mkdirat+0x466/0x7b0 fs/namei.c:4060\n __do_sys_mkdirat fs/namei.c:4075 [inline]\n __se_sys_mkdirat fs/namei.c:4073 [inline]\n __ia32_sys_mkdirat+0xc4/0x120 fs/namei.c:4073\n do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]\n __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178\n do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203\n do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246\n entry_SYSENTER_compat_after_hwframe+0x70/0x82\n\nCPU: 1 PID: 4625 Comm: syz-executor.2 Not tainted 6.1.0-rc4-syzkaller-62821-gcb231e2f67ec #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022\n=====================================================\n\nNow, 'ext4_alloc_inode()' didn't init 'ei->i_flags'. If new inode failed\nbefore set 'ei->i_flags' in '__ext4_new_inode()', then do 'iput()'. As after\n6bc0d63dad7f commit will access 'ei->i_flags' in 'ext4_evict_inode()' which\nwill lead to access uninit-value.\nTo solve above issue just init 'ei->i_flags' in 'ext4_alloc_inode()'."
    }
  ],
  "lastModified": "2026-06-17T05:23:45.890",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0D004331-7D50-42AD-826E-F0E24247F1D8",
              "versionEndExcluding": "5.15.87",
              "versionStartIncluding": "5.15.61"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B60CAFE2-08C3-461B-B5F8-25BEB0C9853E",
              "versionEndExcluding": "5.19",
              "versionStartIncluding": "5.18.18"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "DF07DE24-E077-48C2-A075-11E5CC621BA2",
              "versionEndExcluding": "6.0.18",
              "versionStartIncluding": "5.19.2"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "BC4189D9-5478-4E88-A78D-9C1DE29B217C",
              "versionEndExcluding": "6.1.4",
              "versionStartIncluding": "6.1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.10.163:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "3945F890-31A5-4AEC-BB5F-CB003ED01C70"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}