Vulnerability-Lookup

FKIE_CVE-2026-89703

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: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations nfsd4_drop_revoked_stid() handles FREE_STATEID for admin-revoked delegations but does not set SC_STATUS_FREED before releasing cl_lock. revoke_delegation() uses this flag to detect whether FREE_STATEID has already processed the delegation -- without it, the freed delegation is added to cl_revoked via list_add(), producing a use-after-free when cl_revoked is later traversed in __destroy_client(). The SC_STATUS_REVOKED path in nfsd4_free_stateid() (line 7983) already sets SC_STATUS_FREED correctly. Apply the same pattern to the SC_STATUS_ADMIN_REVOKED path in nfsd4_drop_revoked_stid().

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/1e4795766719ffd74b8cf0f2fde4a1350f8326bf
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/650d370cfbc66a96dd14d517bd704689b5bda4e5
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a6d89032e5c6620d5bb44582a72555ce07bf1c2e
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d832a0587528853d45481d1faf75d4b5d062adaf

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": "d832a0587528853d45481d1faf75d4b5d062adaf",
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "versionType": "git"
            },
            {
              "lessThan": "1e4795766719ffd74b8cf0f2fde4a1350f8326bf",
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "versionType": "git"
            },
            {
              "lessThan": "a6d89032e5c6620d5bb44582a72555ce07bf1c2e",
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "versionType": "git"
            },
            {
              "lessThan": "650d370cfbc66a96dd14d517bd704689b5bda4e5",
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "967faa26f313a62e7bebc55d5b8122eaee43b929",
              "versionType": "git"
            },
            {
              "lessThan": "6.12",
              "status": "affected",
              "version": "6.11.6",
              "versionType": "semver"
            }
          ]
        },
        {
          "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": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "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: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations\n\nnfsd4_drop_revoked_stid() handles FREE_STATEID for admin-revoked\ndelegations but does not set SC_STATUS_FREED before releasing cl_lock.\nrevoke_delegation() uses this flag to detect whether FREE_STATEID has\nalready processed the delegation -- without it, the freed delegation is\nadded to cl_revoked via list_add(), producing a use-after-free when\ncl_revoked is later traversed in __destroy_client().\n\nThe SC_STATUS_REVOKED path in nfsd4_free_stateid() (line 7983) already\nsets SC_STATUS_FREED correctly. Apply the same pattern to the\nSC_STATUS_ADMIN_REVOKED path in nfsd4_drop_revoked_stid()."
    }
  ],
  "id": "CVE-2026-89703",
  "lastModified": "2026-09-13T07:17:35.860",
  "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": "2026-09-11T20:19:57.537",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1e4795766719ffd74b8cf0f2fde4a1350f8326bf"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/650d370cfbc66a96dd14d517bd704689b5bda4e5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a6d89032e5c6620d5bb44582a72555ce07bf1c2e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d832a0587528853d45481d1faf75d4b5d062adaf"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-89703 (GCVE-0-2026-89703)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:46 – Updated: 2026-09-13 06:33

Title

nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations

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

4 references

URL	Tags
https://git.kernel.org/stable/c/d832a0587528853d4…
https://git.kernel.org/stable/c/1e4795766719ffd74…
https://git.kernel.org/stable/c/a6d89032e5c6620d5…
https://git.kernel.org/stable/c/650d370cfbc66a96d…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a , < d832a0587528853d45481d1faf75d4b5d062adaf (git) Affected: 8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a , < 1e4795766719ffd74b8cf0f2fde4a1350f8326bf (git) Affected: 8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a , < a6d89032e5c6620d5bb44582a72555ce07bf1c2e (git) Affected: 8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a , < 650d370cfbc66a96dd14d517bd704689b5bda4e5 (git) Affected: 967faa26f313a62e7bebc55d5b8122eaee43b929 (git) Affected: 6.11.6 , < 6.12 (semver)
Linux	Linux	Affected: 6.12 Unaffected: 0 , < 6.12 (semver) Unaffected: 6.12.109 , ≤ 6.12.* (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/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d832a0587528853d45481d1faf75d4b5d062adaf",
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "versionType": "git"
            },
            {
              "lessThan": "1e4795766719ffd74b8cf0f2fde4a1350f8326bf",
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "versionType": "git"
            },
            {
              "lessThan": "a6d89032e5c6620d5bb44582a72555ce07bf1c2e",
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "versionType": "git"
            },
            {
              "lessThan": "650d370cfbc66a96dd14d517bd704689b5bda4e5",
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "967faa26f313a62e7bebc55d5b8122eaee43b929",
              "versionType": "git"
            },
            {
              "lessThan": "6.12",
              "status": "affected",
              "version": "6.11.6",
              "versionType": "semver"
            }
          ]
        },
        {
          "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": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "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": "6.12.109",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.11.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations\n\nnfsd4_drop_revoked_stid() handles FREE_STATEID for admin-revoked\ndelegations but does not set SC_STATUS_FREED before releasing cl_lock.\nrevoke_delegation() uses this flag to detect whether FREE_STATEID has\nalready processed the delegation -- without it, the freed delegation is\nadded to cl_revoked via list_add(), producing a use-after-free when\ncl_revoked is later traversed in __destroy_client().\n\nThe SC_STATUS_REVOKED path in nfsd4_free_stateid() (line 7983) already\nsets SC_STATUS_FREED correctly. Apply the same pattern to the\nSC_STATUS_ADMIN_REVOKED path in nfsd4_drop_revoked_stid()."
        }
      ],
      "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 UAF is in nfsd nfsd4_drop_revoked_stid()/revoke_delegation() in fs/nfsd/nfs4state.c. A remote NFSv4 peer reaches it over TCP/2049 via svc_process to nfsd_dispatch to nfsd4_proc_compound: SEQUENCE then FREE_STATEID (ALLOWED_WITHOUT_FH), or a v4.0 op that hits nfsd40_drop_revoked_stid on an admin-revoked delegation.\nAC:L - The attacker holds a delegation and retries FREE_STATEID (or v4.0 use of that stateid) while nfsd4_revoke_states() unhashes with ADMIN_REVOKED and revoke_delegation() runs, then DESTROY_CLIENTID/expire so __destroy_client() walks cl_revoked. They control the NFS side of the race; unexport is a routine nfsd operational condition, not an uninfluenced layout.\nPR:N - Typical nfsd deployments use AUTH_SYS/AUTH_NULL with no cryptographic RPC authentication. Any host allowed by the export can EXCHANGE_ID/CREATE_SESSION or SETCLIENTID, OPEN to receive a delegation, and issue FREE_STATEID; no local Linux account or capability on the NFS server is required.\nUI:N - The attacker sends the NFSv4 compounds that obtain the delegation, FREE_STATEID, and client teardown. Administrative unlock_filesystem/unexport is a server operational condition (exportfs -u or volume detach), not a required victim user action such as mounting or opening a file.\nS:U - The use-after-free corrupts a kmalloc\u0027d nfs4_delegation (deleg_slab) in the NFS server kernel. Impact stays in that host kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - Without SC_STATUS_FREED, revoke_delegation() list_add()s a kmem_cache_free\u0027d nfs4_delegation onto cl_revoked (KMEM_CACHE flags 0, not SLAB_TYPESAFE_BY_RCU). __destroy_client() then walks that freed object; slab reuse yields an arbitrary kernel-read primitive. Per guidance a UAF is C:H.\nI:H - list_add on the freed dl_recall_lru and later list_del_init/nfs4_put_stid in __destroy_client() write through reclaimed deleg_slab, including sc_free. That is a heap-spray write and control-flow hijack primitive. Per guidance a UAF is I:H.\nA:H - Use-after-free of nfs4_delegation when __destroy_client() traverses cl_revoked oopses or panics the nfsd thread even without full exploitation, fully denying service of the NFS server host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:33:24.763Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d832a0587528853d45481d1faf75d4b5d062adaf"
        },
        {
          "url": "https://git.kernel.org/stable/c/1e4795766719ffd74b8cf0f2fde4a1350f8326bf"
        },
        {
          "url": "https://git.kernel.org/stable/c/a6d89032e5c6620d5bb44582a72555ce07bf1c2e"
        },
        {
          "url": "https://git.kernel.org/stable/c/650d370cfbc66a96dd14d517bd704689b5bda4e5"
        }
      ],
      "title": "nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89703",
    "datePublished": "2026-09-11T19:46:20.280Z",
    "dateReserved": "2026-09-11T19:38:34.750Z",
    "dateUpdated": "2026-09-13T06:33:24.763Z",
    "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

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.