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CVE-2026-72472

Estado: RecibidaCrítica (9.8)—

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

nfs: use nfsi->rwsem to protect traversal of the file lock list

Lingfeng identified a bug and suggested two solutions, but both appear to have issues.

Generally, we cannot release flc_lock while iterating over the file lock list to avoid use-after-free (UAF) problems with file locks. However, functions like nfs_delegation_claim_locks and nfs4_reclaim_locks cannot adhere to this rule because recover_lock or nfs4_lock_delegation_recall may take a long time.

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To resolve this, NFS switches to using nfsi->rwsem for the same protection, and nfs_reclaim_locks follows this approach. Although nfs_delegation_claim_locks uses so_delegreturn_mutex instead, this is inadequate since a single inode can have multiple nfs4_state instances. Therefore, the fix is to also use nfsi->rwsem in this case.

Furthermore, after commit c69899a17ca4 ("NFSv4: Update of VFS byte range lock must be atomic with the stateid update"), the functions nfs4_locku_done and nfs4_lock_done also break this rule because they call locks_lock_inode_wait without holding nfsi->rwsem. Simply adding this protection could cause many deadlocks, so instead, the call to locks_lock_inode_wait is moved into _nfs4_proc_setlk. Regarding the bug fixed by commit c69899a17ca4 ("NFSv4: Update of VFS byte range lock must be atomic with the stateid update"), it has been resolved after commit 0460253913e5 ("NFSv4: nfs4_do_open() is incorrectly triggering state recovery") because all slots are drained before calling nfs4_do_reclaim, which prevents concurrent stateid changes along this path. Also, nfs_delegation_claim_locks does not cause this concurrency either since when _nfs4_proc_setlk is called with NFS_DELEGATED_STATE, no RPC is sent, so nfs4_lock_done is not called. Therefore, nfs4_lock_delegation_recall from nfs_delegation_claim_locks is the first time the stateid is set.

CVSS

Probabilidad de explotación (EPSS)

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.

Vulnerabilidad de denegación de servicio por race condition en el kernel de Linux (AV:N, vector red sin privilegios). El UAF puede causar pánico del kernel o escalada local. Acceso remoto + disponibilidad crítica.

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

Filter Network TrafficVulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkApplication Isolation and Sandboxing

Tecnologías afectadas (1)

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

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-72472",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "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": "c69899a17ca4836230720e65493942d9582a0424",
              "lessThan": "1cda95bf2e9c0e6b63545b7565fe4a1e474322f4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c69899a17ca4836230720e65493942d9582a0424",
              "lessThan": "f161ef7b0dd2f51fdb002ba4a4e9bf0ee7409218",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c69899a17ca4836230720e65493942d9582a0424",
              "lessThan": "e68035178e65e2b3aa386ce61202ff33724ae418",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c69899a17ca4836230720e65493942d9582a0424",
              "lessThan": "4837fb36219e6c08b666bc31a86841bad8526358",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/nfs/delegation.c",
            "fs/nfs/nfs4proc.c",
            "include/linux/nfs_xdr.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/nfs/delegation.c",
            "fs/nfs/nfs4proc.c",
            "include/linux/nfs_xdr.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:22:21.313",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1cda95bf2e9c0e6b63545b7565fe4a1e474322f4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4837fb36219e6c08b666bc31a86841bad8526358",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e68035178e65e2b3aa386ce61202ff33724ae418",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f161ef7b0dd2f51fdb002ba4a4e9bf0ee7409218",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfs: use nfsi->rwsem to protect traversal of the file lock list\n\nLingfeng identified a bug and suggested two solutions, but both appear\nto have issues.\n\nGenerally, we cannot release flc_lock while iterating over the file lock\nlist to avoid use-after-free (UAF) problems with file locks. However,\nfunctions like nfs_delegation_claim_locks and nfs4_reclaim_locks cannot\nadhere to this rule because recover_lock or nfs4_lock_delegation_recall\nmay take a long time. To resolve this, NFS switches to using nfsi->rwsem\nfor the same protection, and nfs_reclaim_locks follows this approach.\nAlthough nfs_delegation_claim_locks uses so_delegreturn_mutex instead,\nthis is inadequate since a single inode can have multiple nfs4_state\ninstances. Therefore, the fix is to also use nfsi->rwsem in this case.\n\nFurthermore, after commit c69899a17ca4 (\"NFSv4: Update of VFS byte range\nlock must be atomic with the stateid update\"), the functions\nnfs4_locku_done and nfs4_lock_done also break this rule because they\ncall locks_lock_inode_wait without holding nfsi->rwsem. Simply adding\nthis protection could cause many deadlocks, so instead, the call to\nlocks_lock_inode_wait is moved into _nfs4_proc_setlk. Regarding the bug\nfixed by commit c69899a17ca4 (\"NFSv4: Update of VFS byte range\nlock must be atomic with the stateid update\"), it has been resolved\nafter commit 0460253913e5 (\"NFSv4: nfs4_do_open() is incorrectly triggering\nstate recovery\") because all slots are drained before calling\nnfs4_do_reclaim, which prevents concurrent stateid changes along this path.\nAlso, nfs_delegation_claim_locks does not cause this concurrency either\nsince when _nfs4_proc_setlk is called with NFS_DELEGATED_STATE, no RPC is\nsent, so nfs4_lock_done is not called. Therefore,\nnfs4_lock_delegation_recall from nfs_delegation_claim_locks is the first\ntime the stateid is set."
    }
  ],
  "lastModified": "2026-08-17T06:19:15.137",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}