Vulnerability-Lookup

FKIE_CVE-2026-89676

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-09-13 07:17

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: fix stale s2s_cp_stateids IDR entry for async COPY For an async COPY, nfsd4_copy() called nfs4_init_copy_state() before dup_copy_fields(), so the s2s_cp_stateids IDR was pointed at &u->copy->cp_stateid -- memory in the per-rqstp COMPOUND buffer that is reused by the next request. dup_copy_fields() copies only the value into async_copy, so the IDR slot dangled at the transient buffer for the whole background copy. Any IDR walker then dereferences reused request memory: the laundromat reads cs_type from it and, if the bytes look like an expired NFS4_COPYNOTIFY_STID, follows into refcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has the same exposure via idr_find(). Duplicate the fields first, then register the stateid on the stable async_copy. result->cb_stateid is unchanged.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/14b978e8d05ce018d0afbeb6611833ef91713a02
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d0beaee498e11880e72826026db0e9c9890fc114

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4proc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a",
              "status": "affected",
              "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "versionType": "git"
            },
            {
              "lessThan": "14b978e8d05ce018d0afbeb6611833ef91713a02",
              "status": "affected",
              "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "versionType": "git"
            },
            {
              "lessThan": "d0beaee498e11880e72826026db0e9c9890fc114",
              "status": "affected",
              "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4proc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.20"
            },
            {
              "lessThan": "4.20",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "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: fix stale s2s_cp_stateids IDR entry for async COPY\n\nFor an async COPY, nfsd4_copy() called nfs4_init_copy_state() before\ndup_copy_fields(), so the s2s_cp_stateids IDR was pointed at\n\u0026u-\u003ecopy-\u003ecp_stateid -- memory in the per-rqstp COMPOUND buffer that is\nreused by the next request. dup_copy_fields() copies only the value into\nasync_copy, so the IDR slot dangled at the transient buffer for the whole\nbackground copy. Any IDR walker then dereferences reused request memory:\nthe laundromat reads cs_type from it and, if the bytes look like an\nexpired NFS4_COPYNOTIFY_STID, follows into\nrefcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has\nthe same exposure via idr_find().\n\nDuplicate the fields first, then register the stateid on the stable\nasync_copy. result-\u003ecb_stateid is unchanged."
    }
  ],
  "id": "CVE-2026-89676",
  "lastModified": "2026-09-13T07:17:33.310",
  "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": "2026-09-11T20:19:54.273",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/14b978e8d05ce018d0afbeb6611833ef91713a02"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d0beaee498e11880e72826026db0e9c9890fc114"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-89676 (GCVE-0-2026-89676)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:46 – Updated: 2026-09-13 06:32

Title

nfsd: fix stale s2s_cp_stateids IDR entry for async COPY

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/9b4e5e9ba5ae13808…
https://git.kernel.org/stable/c/14b978e8d05ce018d…
https://git.kernel.org/stable/c/d0beaee498e11880e…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: e0639dc5805a9d4faaa2c07ad98fa853b9529dd3 , < 9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a (git) Affected: e0639dc5805a9d4faaa2c07ad98fa853b9529dd3 , < 14b978e8d05ce018d0afbeb6611833ef91713a02 (git) Affected: e0639dc5805a9d4faaa2c07ad98fa853b9529dd3 , < d0beaee498e11880e72826026db0e9c9890fc114 (git)
Linux	Linux	Affected: 4.20 Unaffected: 0 , < 4.20 (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 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/nfs4proc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a",
              "status": "affected",
              "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "versionType": "git"
            },
            {
              "lessThan": "14b978e8d05ce018d0afbeb6611833ef91713a02",
              "status": "affected",
              "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "versionType": "git"
            },
            {
              "lessThan": "d0beaee498e11880e72826026db0e9c9890fc114",
              "status": "affected",
              "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4proc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.20"
            },
            {
              "lessThan": "4.20",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "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": "6.18.50",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix stale s2s_cp_stateids IDR entry for async COPY\n\nFor an async COPY, nfsd4_copy() called nfs4_init_copy_state() before\ndup_copy_fields(), so the s2s_cp_stateids IDR was pointed at\n\u0026u-\u003ecopy-\u003ecp_stateid -- memory in the per-rqstp COMPOUND buffer that is\nreused by the next request. dup_copy_fields() copies only the value into\nasync_copy, so the IDR slot dangled at the transient buffer for the whole\nbackground copy. Any IDR walker then dereferences reused request memory:\nthe laundromat reads cs_type from it and, if the bytes look like an\nexpired NFS4_COPYNOTIFY_STID, follows into\nrefcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has\nthe same exposure via idr_find().\n\nDuplicate the fields first, then register the stateid on the stable\nasync_copy. result-\u003ecb_stateid is unchanged."
        }
      ],
      "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 - The dangling s2s_cp_stateids pointer is installed by nfsd4_copy in the in-kernel NFSv4.2 server; a remote client reaches it over TCP/2049 via COMPOUND RPCs (EXCHANGE_ID, CREATE_SESSION, OPEN, then async COPY).\nAC:L - The attacker reliably creates the stale IDR entry with async COPY, then either reuses that nfsd thread\u0027s COMPOUND iops buffer with further requests or sends a \u003e8-op compound so the vcalloc\u0027d ops array is kvfree_rcu\u0027d, and later walks the IDR via OFFLOAD_CANCEL/READ or the laundromat; no condition outside attacker control is required.\nPR:N - Typical nfsd deployments use AUTH_SYS or AUTH_NULL with IP-based exports, so a remote peer that can reach the export can create an NFSv4.2 session, OPEN readable and writable files, and issue async COPY without a local account or capability on the NFS server.\nUI:N - Exploitation requires only attacker-sent NFS RPCs against a running nfsd export; no victim user action such as mounting a filesystem or opening a local file on the server is required.\nS:U - The stale IDR dereference corrupts kernel nfsd copy and copy-notify state on the NFS server host and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - The IDR retains a pointer into reused per-rqstp COMPOUND memory or a kvfree_rcu\u0027d ops array; the laundromat and manage_cpntf_state then read cs_type and adjacent fields from attacker-controlled reused or sprayed memory, a use-after-free disclosure primitive.\nI:H - When reused bytes look like an expired NFS4_COPYNOTIFY_STID, the laundromat and manage_cpntf_state perform list_del, refcount_dec, and kfree on the garbage object, a use-after-free write/free primitive that enables heap corruption and control-flow hijacking.\nA:H - kfree or list_del on the dangling COMPOUND buffer or sprayed slab oopses or panics nfsd worker threads, and the attacker can repeat async COPY plus IDR walks to take down the NFS server host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:32:58.688Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a"
        },
        {
          "url": "https://git.kernel.org/stable/c/14b978e8d05ce018d0afbeb6611833ef91713a02"
        },
        {
          "url": "https://git.kernel.org/stable/c/d0beaee498e11880e72826026db0e9c9890fc114"
        }
      ],
      "title": "nfsd: fix stale s2s_cp_stateids IDR entry for async COPY",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89676",
    "datePublished": "2026-09-11T19:46:00.382Z",
    "dateReserved": "2026-09-11T19:38:34.747Z",
    "dateUpdated": "2026-09-13T06:32:58.688Z",
    "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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