Vulnerability-Lookup

FKIE_CVE-2026-90037

Vulnerability from fkie_nvd - Published: 2026-09-16 11:17 - Updated: 2026-09-16 15:18

Severity

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

Summary

In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent client use-after-free during close_lru reaping An nfs4_openowner left on nn->close_lru after its final CLOSE keeps its last closed stateid in oo_last_closed_stid, holding only a raw pointer to its nfs4_client. The laundromat reaps timed-out entries, drops nn->client_lock, and calls nfs4_put_stid(), which dereferences the client through cl_lock. Nothing pins the client across that window, so a concurrent force_expire_client() can free it and nfs4_put_stid() reads freed memory. __destroy_client() hits the same race, walking clp->cl_openowners without cl_lock. Pin the client with cl_rpc_users before dropping client_lock, and skip clients already expiring. __destroy_client() then cleans up its own close_lru entries through release_last_closed_stateid(), so teardown no longer races the laundromat.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2330b788d732f43668b965b3105b37ceb276dfea
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/83dd59ac1c3455c2c7d8ddb582d980a13199b9b3
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "83dd59ac1c3455c2c7d8ddb582d980a13199b9b3",
              "status": "affected",
              "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c",
              "versionType": "git"
            },
            {
              "lessThan": "e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1",
              "status": "affected",
              "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c",
              "versionType": "git"
            },
            {
              "lessThan": "2330b788d732f43668b965b3105b37ceb276dfea",
              "status": "affected",
              "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.17"
            },
            {
              "lessThan": "3.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during close_lru reaping\n\nAn nfs4_openowner left on nn-\u003eclose_lru after its final CLOSE keeps\nits last closed stateid in oo_last_closed_stid, holding only a raw\npointer to its nfs4_client. The laundromat reaps timed-out entries,\ndrops nn-\u003eclient_lock, and calls nfs4_put_stid(), which dereferences\nthe client through cl_lock. Nothing pins the client across that\nwindow, so a concurrent force_expire_client() can free it and\nnfs4_put_stid() reads freed memory. __destroy_client() hits the same\nrace, walking clp-\u003ecl_openowners without cl_lock.\n\nPin the client with cl_rpc_users before dropping client_lock, and\nskip clients already expiring. __destroy_client() then cleans up its\nown close_lru entries through release_last_closed_stateid(), so\nteardown no longer races the laundromat."
    }
  ],
  "id": "CVE-2026-90037",
  "lastModified": "2026-09-16T15:18:26.540",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-16T11:17:16.910",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2330b788d732f43668b965b3105b37ceb276dfea"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/83dd59ac1c3455c2c7d8ddb582d980a13199b9b3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-90037 (GCVE-0-2026-90037)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:33 – Updated: 2026-09-16 14:41

Title

NFSD: Prevent client use-after-free during close_lru reaping

Summary

Severity

9.8 (Critical)


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

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/83dd59ac1c3455c2c…
https://git.kernel.org/stable/c/e57a9ed34ea8c17e8…
https://git.kernel.org/stable/c/2330b788d732f4366…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 217526e7ecc9f6f243e976772e81eab7ab986a4c , < 83dd59ac1c3455c2c7d8ddb582d980a13199b9b3 (git) Affected: 217526e7ecc9f6f243e976772e81eab7ab986a4c , < e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1 (git) Affected: 217526e7ecc9f6f243e976772e81eab7ab986a4c , < 2330b788d732f43668b965b3105b37ceb276dfea (git)
Linux	Linux	Affected: 3.17 Unaffected: 0 , < 3.17 (semver) Unaffected: 6.18.51 , ≤ 6.18.* (semver) Unaffected: 7.2.5 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "83dd59ac1c3455c2c7d8ddb582d980a13199b9b3",
              "status": "affected",
              "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c",
              "versionType": "git"
            },
            {
              "lessThan": "e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1",
              "status": "affected",
              "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c",
              "versionType": "git"
            },
            {
              "lessThan": "2330b788d732f43668b965b3105b37ceb276dfea",
              "status": "affected",
              "version": "217526e7ecc9f6f243e976772e81eab7ab986a4c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.17"
            },
            {
              "lessThan": "3.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during close_lru reaping\n\nAn nfs4_openowner left on nn-\u003eclose_lru after its final CLOSE keeps\nits last closed stateid in oo_last_closed_stid, holding only a raw\npointer to its nfs4_client. The laundromat reaps timed-out entries,\ndrops nn-\u003eclient_lock, and calls nfs4_put_stid(), which dereferences\nthe client through cl_lock. Nothing pins the client across that\nwindow, so a concurrent force_expire_client() can free it and\nnfs4_put_stid() reads freed memory. __destroy_client() hits the same\nrace, walking clp-\u003ecl_openowners without cl_lock.\n\nPin the client with cl_rpc_users before dropping client_lock, and\nskip clients already expiring. __destroy_client() then cleans up its\nown close_lru entries through release_last_closed_stateid(), so\nteardown no longer races the laundromat."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - nfsd is the in-kernel NFS server. A remote NFSv4.0 client reaches the UAF over TCP/UDP 2049: CLOSE places the openowner on nn-\u003eclose_lru, and SETCLIENTID_CONFIRM (ALLOWED_WITHOUT_FH) calls expire_client() while nfs4_laundromat() drops client_lock and nfs4_put_stid() uses the unpinned nfs4_client.\nAC:L - The attacker drives both sides: OPEN/CLOSE compounds fill close_lru so the laundromat drops client_lock once per nfs4_put_stid(), and concurrent SETCLIENTID_CONFIRM with matching AUTH_SYS creds replaces the client via expire_client(). FATTR4_LEASE_TIME times the window; flooding close_lru widens it; the race is retryable.\nPR:N - Typical nfsd deployments use AUTH_SYS/AUTH_NULL, so RPC uids are self-asserted. SETCLIENTID and SETCLIENTID_CONFIRM are ALLOWED_WITHOUT_FH; any host allowed by the export can OPEN/CLOSE and replace the client with no local account or capability on the NFS server.\nUI:N - The attacker issues the NFSv4.0 compounds (SETCLIENTID, OPEN, CLOSE, RENEW, SETCLIENTID_CONFIRM) itself. No administrator or other user on the victim server must mount a filesystem, write nfsdfs ctl, or otherwise interact.\nS:U - The use-after-free is of the nfsd nfs4_client object (client_slab) in the NFS server kernel. Impact stays in that kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - After free_client() kmem_cache_free()s the nfs4_client, nfs4_put_stid() still reads cl_lock and cl_stateids. Reclaiming the mergeable client_slab object via further SETCLIENTID discloses kernel heap; a UAF is C:H.\nI:H - nfs4_put_stid() then takes cl_lock and idr_remove()s from cl_stateids on the freed nfs4_client, a slab UAF write concurrent with __destroy_client(). Heap reuse enables arbitrary write and control-flow hijack; a UAF is I:H.\nA:H - Use-after-free of nfs4_client in nfs4_put_stid() (spin_lock of freed cl_lock) oopses or panics the nfsd laundromat worker even without a full exploit, denying service of the NFS server host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T14:41:49.513Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/83dd59ac1c3455c2c7d8ddb582d980a13199b9b3"
        },
        {
          "url": "https://git.kernel.org/stable/c/e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1"
        },
        {
          "url": "https://git.kernel.org/stable/c/2330b788d732f43668b965b3105b37ceb276dfea"
        }
      ],
      "title": "NFSD: Prevent client use-after-free during close_lru reaping",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90037",
    "datePublished": "2026-09-16T10:33:36.673Z",
    "dateReserved": "2026-09-11T19:38:34.782Z",
    "dateUpdated": "2026-09-16T14:41:49.513Z",
    "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.

Detection rules are retrieved from Rulezet.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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