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CVE-2025-40105

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: vfs: Don't leak disconnected dentries on umount When user calls open_by_handle_at() on some inode that is not cached, we will create disconnected dentry for it. If such dentry is a directory, exportfs_decode_fh_raw() will then try to connect this dentry to the dentry tree through reconnect_path(). It may happen for various reasons (such as corrupted fs or race with rename) that the call to lookup_one_unlocked() in reconnect_one() will fail to find the dentry we are trying to reconnect and instead create a new dentry under the parent. Now this dentry will not be marked as disconnected although the parent still may well be disconnected (at least in case this inconsistency happened because the fs is corrupted and .. doesn't point to the real parent directory). This creates inconsistency in disconnected flags but AFAICS it was mostly harmless. At least until commit f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon") which removed adding of most disconnected dentries to sb->s_anon list. Thus after this commit cleanup of disconnected dentries implicitely relies on the fact that dput() will immediately reclaim such dentries. However when some leaf dentry isn't marked as disconnected, as in the scenario described above, the reclaim doesn't happen and the dentries are "leaked". Memory reclaim can eventually reclaim them but otherwise they stay in memory and if umount comes first, we hit infamous "Busy inodes after unmount" bug. Make sure all dentries created under a disconnected parent are marked as disconnected as well.

Severity
HIGH
CVSS score
7.8 (v3.1)
Vulnerability status
Deferred
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-10-30 10:15:34.880000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON 
{
  "id": "CVE-2025-40105",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-10-30T10:15:34.880",
  "lastModified": "2026-10-19T21:10:00.160",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvfs: Don't leak disconnected dentries on umount\n\nWhen user calls open_by_handle_at() on some inode that is not cached, we\nwill create disconnected dentry for it. If such dentry is a directory,\nexportfs_decode_fh_raw() will then try to connect this dentry to the\ndentry tree through reconnect_path(). It may happen for various reasons\n(such as corrupted fs or race with rename) that the call to\nlookup_one_unlocked() in reconnect_one() will fail to find the dentry we\nare trying to reconnect and instead create a new dentry under the\nparent. Now this dentry will not be marked as disconnected although the\nparent still may well be disconnected (at least in case this\ninconsistency happened because the fs is corrupted and .. doesn't point\nto the real parent directory). This creates inconsistency in\ndisconnected flags but AFAICS it was mostly harmless. At least until\ncommit f1ee616214cb (\"VFS: don't keep disconnected dentries on d_anon\")\nwhich removed adding of most disconnected dentries to sb->s_anon list.\nThus after this commit cleanup of disconnected dentries implicitely\nrelies on the fact that dput() will immediately reclaim such dentries.\nHowever when some leaf dentry isn't marked as disconnected, as in the\nscenario described above, the reclaim doesn't happen and the dentries\nare \"leaked\". Memory reclaim can eventually reclaim them but otherwise\nthey stay in memory and if umount comes first, we hit infamous \"Busy\ninodes after unmount\" bug. Make sure all dentries created under a\ndisconnected parent are marked as disconnected as well."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nvfs: No fugar dentries desconectados al desmontar\n\nCuando el usuario llama a open_by_handle_at() en algún inodo que no está en caché, crearemos un dentry desconectado para él. Si dicho dentry es un directorio, exportfs_decode_fh_raw() intentará entonces conectar este dentry al árbol de dentries a través de reconnect_path(). Puede ocurrir por varias razones (como un sistema de archivos corrupto o una condición de carrera con renombrar) que la llamada a lookup_one_unlocked() en reconnect_one() falle en encontrar el dentry que estamos intentando reconectar y en su lugar cree un nuevo dentry bajo el padre. Ahora este dentry no será marcado como desconectado aunque el padre aún podría estar desconectado (al menos en caso de que esta inconsistencia ocurriera porque el sistema de archivos está corrupto y .. no apunta al directorio padre real). Esto crea inconsistencia en las banderas de desconexión pero hasta donde puedo ver era mayormente inofensivo. Al menos hasta el commit f1ee616214cb ('VFS: no mantener dentries desconectados en d_anon') que eliminó la adición de la mayoría de los dentries desconectados a la lista sb->s_anon. Así, después de este commit, la limpieza de los dentries desconectados se basa implícitamente en el hecho de que dput() reclamará inmediatamente dichos dentries. Sin embargo, cuando algún dentry hoja no está marcado como desconectado, como en el escenario descrito anteriormente, la recuperación no ocurre y los dentries se 'fugan'. La recuperación de memoria puede eventualmente reclamarlos, pero de lo contrario permanecen en memoria y si el desmontaje ocurre primero, nos encontramos con el infame error 'Inodos ocupados después del desmontaje'. Asegúrese de que todos los dentries creados bajo un padre desconectado también estén marcados como desconectados."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/dcache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "f1ee616214cb22410e939d963bbb2349c2570f02",
              "lessThan": "b5abafd0aa8d7bcb935c8f91e4cfc2f2820759e4",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1ee616214cb22410e939d963bbb2349c2570f02",
              "lessThan": "20863bb7fbb016379f8227122edfabc5c799bc79",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1ee616214cb22410e939d963bbb2349c2570f02",
              "lessThan": "8004d4b8cbf1bd68a23c160d57287e177c82cc69",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1ee616214cb22410e939d963bbb2349c2570f02",
              "lessThan": "7e0c8aaf4e28918abded547a5147c7d52c4af7d2",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1ee616214cb22410e939d963bbb2349c2570f02",
              "lessThan": "cebfbf40056a4d858b2a3ca59a69936d599bd209",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1ee616214cb22410e939d963bbb2349c2570f02",
              "lessThan": "620f3b0ede9c5cb4976cd0457d0b04ad551e5d6b",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1ee616214cb22410e939d963bbb2349c2570f02",
              "lessThan": "eadc49999fa994d6fbd70c332bd5d5051cc42261",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1ee616214cb22410e939d963bbb2349c2570f02",
              "lessThan": "56094ad3eaa21e6621396cc33811d8f72847a834",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/dcache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "4.16",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "4.16",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.4.301",
              "lessThanOrEqual": "5.4.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.10.246",
              "lessThanOrEqual": "5.10.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.196",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.158",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.114",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.55",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.17.5",
              "lessThanOrEqual": "6.17.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    },
    {
      "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
      "affectedData": [
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.7",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.7",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.7",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.7",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "V3.1.7",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-15T21:56:57.898376Z",
          "id": "CVE-2025-40105",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/20863bb7fbb016379f8227122edfabc5c799bc79",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html",
      "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
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    {
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      "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
    }
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}