Vulnerability-Lookup

FKIE_CVE-2021-47638

Vulnerability from fkie_nvd - Published: 2025-02-26 06:37 - Updated: 2026-08-04 10:17

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fc	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2b3236ecf96db7af5836e1366ce39ace8ce832fa	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3e	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123dd	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6e15ac651484e59d3fa36274	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a90e2dbe66d2647ff95a0442ad2e86482d977fd8	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b9a937f096e608b3368c1abc920d4d640ba2c94f	Patch

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	*

JSON

To clipboard

{
  "affected": [
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      "affectedData": [
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          "product": "Linux",
          "programFiles": [
            "fs/ubifs/dir.c"
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          "vendor": "Linux",
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          "versions": [
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              "version": "4.9"
            },
            {
              "lessThan": "4.9",
              "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",
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            },
            {
              "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"
    }
  ],
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            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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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": "2026-08-04T10:17:11.823",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      },
      {
        "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"
      ],
      "url": "https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123dd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6e15ac651484e59d3fa36274"
    },
    {
      "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"
    }
  ]
}

CVE-2021-47638 (GCVE-0-2021-47638)

Vulnerability from cvelistv5 – Published: 2025-02-26 01:54 – Updated: 2026-08-05 08:48

Title

ubifs: rename_whiteout: Fix double free for whiteout_ui->data

Summary

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

5.5 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-10-01 19:50 UTC

CWE

CWE-415 - Double Free

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6992 records in the last 180 days details

References

8 references

URL	Tags
https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6…
https://git.kernel.org/stable/c/2b3236ecf96db7af5…
https://git.kernel.org/stable/c/14276d38c89a17036…
https://git.kernel.org/stable/c/a90e2dbe66d2647ff…
https://git.kernel.org/stable/c/2ad07009c459e56eb…
https://git.kernel.org/stable/c/b9a937f096e608b33…
https://git.kernel.org/stable/c/6d7a158a7363c1f66…
https://git.kernel.org/stable/c/40a8f0d5e7b3999f0…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798 , < 8b3c7be16f3f4dfd6e15ac651484e59d3fa36274 (git) Affected: 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798 , < 2b3236ecf96db7af5836e1366ce39ace8ce832fa (git) Affected: 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798 , < 14276d38c89a170363e90b6ac0a53c3cf61b87fc (git) Affected: 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798 , < a90e2dbe66d2647ff95a0442ad2e86482d977fd8 (git) Affected: 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798 , < 2ad07009c459e56ebdcc089d850d664660fdb742 (git) Affected: 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798 , < b9a937f096e608b3368c1abc920d4d640ba2c94f (git) Affected: 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798 , < 6d7a158a7363c1f6604aa47ae1a280a5c65123dd (git) Affected: 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798 , < 40a8f0d5e7b3999f096570edab71c345da812e3e (git)
Linux	Linux	Affected: 4.9 Unaffected: 0 , < 4.9 (semver) Unaffected: 4.14.276 , ≤ 4.14.* (semver) Unaffected: 4.19.238 , ≤ 4.19.* (semver) Unaffected: 5.4.189 , ≤ 5.4.* (semver) Unaffected: 5.10.110 , ≤ 5.10.* (semver) Unaffected: 5.15.33 , ≤ 5.15.* (semver) Unaffected: 5.16.19 , ≤ 5.16.* (semver) Unaffected: 5.17.2 , ≤ 5.17.* (semver) Unaffected: 5.18 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2021-47638",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-10-01T19:50:47.905064Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-415",
                "description": "CWE-415 Double Free",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-10-01T19:57:08.545Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ubifs/dir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8b3c7be16f3f4dfd6e15ac651484e59d3fa36274",
              "status": "affected",
              "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798",
              "versionType": "git"
            },
            {
              "lessThan": "2b3236ecf96db7af5836e1366ce39ace8ce832fa",
              "status": "affected",
              "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798",
              "versionType": "git"
            },
            {
              "lessThan": "14276d38c89a170363e90b6ac0a53c3cf61b87fc",
              "status": "affected",
              "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798",
              "versionType": "git"
            },
            {
              "lessThan": "a90e2dbe66d2647ff95a0442ad2e86482d977fd8",
              "status": "affected",
              "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798",
              "versionType": "git"
            },
            {
              "lessThan": "2ad07009c459e56ebdcc089d850d664660fdb742",
              "status": "affected",
              "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798",
              "versionType": "git"
            },
            {
              "lessThan": "b9a937f096e608b3368c1abc920d4d640ba2c94f",
              "status": "affected",
              "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798",
              "versionType": "git"
            },
            {
              "lessThan": "6d7a158a7363c1f6604aa47ae1a280a5c65123dd",
              "status": "affected",
              "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798",
              "versionType": "git"
            },
            {
              "lessThan": "40a8f0d5e7b3999f096570edab71c345da812e3e",
              "status": "affected",
              "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798",
              "versionType": "git"
            }
          ]
        },
        {
          "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": [
            {
              "status": "affected",
              "version": "4.9"
            },
            {
              "lessThan": "4.9",
              "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.14.276",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.19.238",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.189",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.110",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.33",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.16.19",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.17.2",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.18",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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)."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached via renameat2(RENAME_WHITEOUT) on a mounted UBIFS volume (syscall \u2192 vfs_rename \u2192 ubifs_rename \u2192 do_rename), not via network packet processing.\nAC:L - An attacker with write access can reliably force the whiteout ubifs_budget_space() failure by exhausting free space or concurrent budget pressure after earlier budgets succeed; no conditions outside attacker control are required.\nPR:L - RENAME_WHITEOUT needs only directory write/exec permission; CAP_MKNOD is not required (unprivileged whiteouts since a3c751a50fe6), so a normal local user on writable UBIFS (e.g. Android/embedded data) can trigger it.\nUI:N - The attacker issues renameat2 themselves on an already-mounted writable UBIFS; no separate victim action is required.\nS:U - Impact is confined to the local kernel/host authority (privilege escalation or crash); it does not cross a VM, IOMMU, or other security boundary.\nC:H - This is a double-free of a kmalloc object with an RCU grace period before the second free, enabling heap reclaim and arbitrary read primitives from corrupted allocator/object state.\nI:H - The same double-free/heap corruption is exploitable for arbitrary write and control-flow hijacking via spraying the reclaimed kmalloc-8 slot between the two frees.\nA:H - The double-free triggers KASAN/invalid-free and can oops or panic the kernel even without full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:48:43.826Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6e15ac651484e59d3fa36274"
        },
        {
          "url": "https://git.kernel.org/stable/c/2b3236ecf96db7af5836e1366ce39ace8ce832fa"
        },
        {
          "url": "https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fc"
        },
        {
          "url": "https://git.kernel.org/stable/c/a90e2dbe66d2647ff95a0442ad2e86482d977fd8"
        },
        {
          "url": "https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742"
        },
        {
          "url": "https://git.kernel.org/stable/c/b9a937f096e608b3368c1abc920d4d640ba2c94f"
        },
        {
          "url": "https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123dd"
        },
        {
          "url": "https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3e"
        }
      ],
      "title": "ubifs: rename_whiteout: Fix double free for whiteout_ui-\u003edata",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47638",
    "datePublished": "2025-02-26T01:54:11.178Z",
    "dateReserved": "2025-02-26T01:48:21.519Z",
    "dateUpdated": "2026-08-05T08:48:43.826Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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