FKIE_CVE-2021-47638

Vulnerability from fkie_nvd - Published: 2025-02-26 06:37 - Updated: 2026-06-17 04:18
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ubifs: rename_whiteout: Fix double free for whiteout_ui->data 'whiteout_ui->data' will be freed twice if space budget fail for rename whiteout operation as following process: rename_whiteout dev = kmalloc whiteout_ui->data = dev kfree(whiteout_ui->data) // Free first time iput(whiteout) ubifs_free_inode kfree(ui->data) // Double free! KASAN reports: ================================================================== BUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70 Call Trace: kfree+0x117/0x490 ubifs_free_inode+0x4f/0x70 [ubifs] i_callback+0x30/0x60 rcu_do_batch+0x366/0xac0 __do_softirq+0x133/0x57f Allocated by task 1506: kmem_cache_alloc_trace+0x3c2/0x7a0 do_rename+0x9b7/0x1150 [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 Freed by task 1506: kfree+0x117/0x490 do_rename.cold+0x53/0x8a [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 The buggy address belongs to the object at ffff88810238bed8 which belongs to the cache kmalloc-8 of size 8 ================================================================== Let ubifs_free_inode() free 'whiteout_ui->data'. BTW, delete unused assignment 'whiteout_ui->data_len = 0', process 'ubifs_evict_inode() -> ubifs_jnl_delete_inode() -> ubifs_jnl_write_inode()' doesn't need it (because 'inc_nlink(whiteout)' won't be excuted by 'goto out_release', and the nlink of whiteout inode is 0).
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fcPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2b3236ecf96db7af5836e1366ce39ace8ce832faPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3ePatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123ddPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6e15ac651484e59d3fa36274Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a90e2dbe66d2647ff95a0442ad2e86482d977fd8Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b9a937f096e608b3368c1abc920d4d640ba2c94fPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
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          "product": "Linux",
          "programFiles": [
            "fs/ubifs/dir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ubifs/dir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "4.9"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.14.*",
              "status": "unaffected",
              "version": "4.14.276",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.19.*",
              "status": "unaffected",
              "version": "4.19.238",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.33",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.16.*",
              "status": "unaffected",
              "version": "5.16.19",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.17.*",
              "status": "unaffected",
              "version": "5.17.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
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          "negate": false,
          "operator": "OR"
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nubifs: rename_whiteout: Fix double free for whiteout_ui-\u003edata\n\n\u0027whiteout_ui-\u003edata\u0027 will be freed twice if space budget fail for\nrename whiteout operation as following process:\n\nrename_whiteout\n  dev = kmalloc\n  whiteout_ui-\u003edata = dev\n  kfree(whiteout_ui-\u003edata)  // Free first time\n  iput(whiteout)\n    ubifs_free_inode\n      kfree(ui-\u003edata)\t    // Double free!\n\nKASAN reports:\n==================================================================\nBUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70\nCall Trace:\n  kfree+0x117/0x490\n  ubifs_free_inode+0x4f/0x70 [ubifs]\n  i_callback+0x30/0x60\n  rcu_do_batch+0x366/0xac0\n  __do_softirq+0x133/0x57f\n\nAllocated by task 1506:\n  kmem_cache_alloc_trace+0x3c2/0x7a0\n  do_rename+0x9b7/0x1150 [ubifs]\n  ubifs_rename+0x106/0x1f0 [ubifs]\n  do_syscall_64+0x35/0x80\n\nFreed by task 1506:\n  kfree+0x117/0x490\n  do_rename.cold+0x53/0x8a [ubifs]\n  ubifs_rename+0x106/0x1f0 [ubifs]\n  do_syscall_64+0x35/0x80\n\nThe buggy address belongs to the object at ffff88810238bed8 which\nbelongs to the cache kmalloc-8 of size 8\n==================================================================\n\nLet ubifs_free_inode() free \u0027whiteout_ui-\u003edata\u0027. BTW, delete unused\nassignment \u0027whiteout_ui-\u003edata_len = 0\u0027, process \u0027ubifs_evict_inode()\n-\u003e ubifs_jnl_delete_inode() -\u003e ubifs_jnl_write_inode()\u0027 doesn\u0027t need it\n(because \u0027inc_nlink(whiteout)\u0027 won\u0027t be excuted by \u0027goto out_release\u0027,\n and the nlink of whiteout inode is 0)."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ubifs: rename_whiteout: Se corrige la doble liberaci\u00f3n para whiteout_ui-\u0026gt;data \u0027whiteout_ui-\u0026gt;data\u0027 se liberar\u00e1 dos veces si el presupuesto de espacio falla para la operaci\u00f3n de cambio de nombre de whiteout como el siguiente proceso: rename_whiteout dev = kmalloc whiteout_ui-\u0026gt;data = dev kfree(whiteout_ui-\u0026gt;data) // Libera la primera vez iput(whiteout) ubifs_free_inode kfree(ui-\u0026gt;data) // \u00a1Doble liberaci\u00f3n! KASAN informa: ==================================================================== ERROR: KASAN: liberaci\u00f3n doble o liberaci\u00f3n no v\u00e1lida en ubifs_free_inode+0x4f/0x70 Seguimiento de llamadas: kfree+0x117/0x490 ubifs_free_inode+0x4f/0x70 [ubifs] i_callback+0x30/0x60 rcu_do_batch+0x366/0xac0 __do_softirq+0x133/0x57f Asignado por la tarea 1506: kmem_cache_alloc_trace+0x3c2/0x7a0 do_rename+0x9b7/0x1150 [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 Liberado por la tarea 1506: kfree+0x117/0x490 do_rename.cold+0x53/0x8a [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 La direcci\u00f3n con errores pertenece al objeto en ffff88810238bed8 que pertenece al cach\u00e9 kmalloc-8 de tama\u00f1o 8 ===================================================================== Deje que ubifs_free_inode() libere \u0027whiteout_ui-\u0026gt;data\u0027. Por cierto, elimine la asignaci\u00f3n no utilizada \u0027whiteout_ui-\u0026gt;data_len = 0\u0027, el proceso \u0027ubifs_evict_inode() -\u0026gt; ubifs_jnl_delete_inode() -\u0026gt; ubifs_jnl_write_inode()\u0027 no lo necesita (porque \u0027inc_nlink(whiteout)\u0027 no ser\u00e1 ejecutado por \u0027goto out_release\u0027, y el nlink del inodo whiteout es 0)."
    }
  ],
  "id": "CVE-2021-47638",
  "lastModified": "2026-06-17T04:18:12.863",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2021-47638",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2025-10-01T19:50:47.905064Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2025-02-26T06:37:05.580",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
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      "url": "https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "url": "https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742"
    },
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      "url": "https://git.kernel.org/stable/c/2b3236ecf96db7af5836e1366ce39ace8ce832fa"
    },
    {
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      "url": "https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3e"
    },
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      "url": "https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123dd"
    },
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    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/a90e2dbe66d2647ff95a0442ad2e86482d977fd8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/b9a937f096e608b3368c1abc920d4d640ba2c94f"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-415"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-415"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.