CVE-2026-89669 (GCVE-0-2026-89669)
Vulnerability from cvelistv5
Published
2026-09-11 19:45
Modified
2026-10-19 08:50
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: initialize copy-notify stateid before publishing it nfsd4_copy_notify() finished initializing the cpntf state after nfs4_alloc_init_cpntf_state() had already linked it into the s2s_cp_stateids IDR and the parent's sc_cp_list, with cs_count == 1 (the membership reference) and none held for the caller. A racing OFFLOAD_CANCEL (crafted cl_id == nn->s2s_cp_cl_id plus the guessable so_id) could reach manage_cpntf_state() and free the entry, turning the caller's subsequent cpn_cnr_stateid read and cp_p_stateid/cp_p_clid writes into use-after-free. The owning clientid was also only recorded after publication, so it could not gate an ownership check in that window. Record cp_p_stateid and cp_p_clid inside nfs4_alloc_init_cpntf_state() before nfs4_init_cp_state() publishes the entry, and return it with an extra reference. The caller reads the stateid under that reference and drops it with nfs4_put_cpntf_state(); on a late error the laundromat reaps the entry.
References
Impacted products
Vendor Product Version
Linux Linux Version: 624322f1adc58acd0b69f77a6ddc764207e97241
Version: 624322f1adc58acd0b69f77a6ddc764207e97241
Version: 624322f1adc58acd0b69f77a6ddc764207e97241
Version: 624322f1adc58acd0b69f77a6ddc764207e97241
Version: 624322f1adc58acd0b69f77a6ddc764207e97241
Version: 624322f1adc58acd0b69f77a6ddc764207e97241
Version: 624322f1adc58acd0b69f77a6ddc764207e97241
Version: 624322f1adc58acd0b69f77a6ddc764207e97241
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4proc.c",
            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "863b6e995665472f2af5be2436a874ab6a9e5ac6",
              "status": "affected",
              "version": "624322f1adc58acd0b69f77a6ddc764207e97241",
              "versionType": "git"
            },
            {
              "lessThan": "d18d36395d973ef7372c8e6724970585f75b5c0b",
              "status": "affected",
              "version": "624322f1adc58acd0b69f77a6ddc764207e97241",
              "versionType": "git"
            },
            {
              "lessThan": "4415a692346a39fdb647cbd717eda510159aaf55",
              "status": "affected",
              "version": "624322f1adc58acd0b69f77a6ddc764207e97241",
              "versionType": "git"
            },
            {
              "lessThan": "9caad13b7cfe9ccb90cc405ac77335800e086595",
              "status": "affected",
              "version": "624322f1adc58acd0b69f77a6ddc764207e97241",
              "versionType": "git"
            },
            {
              "lessThan": "e08a3dcaca0505f861e344a387f37f94d95dbdc2",
              "status": "affected",
              "version": "624322f1adc58acd0b69f77a6ddc764207e97241",
              "versionType": "git"
            },
            {
              "lessThan": "a4d7fedcaaf33e60a01e53eafca9041ef966212f",
              "status": "affected",
              "version": "624322f1adc58acd0b69f77a6ddc764207e97241",
              "versionType": "git"
            },
            {
              "lessThan": "4cdef96892f4fa6e70c405b6e8f2fd6972f3b64b",
              "status": "affected",
              "version": "624322f1adc58acd0b69f77a6ddc764207e97241",
              "versionType": "git"
            },
            {
              "lessThan": "129643893b79f8a3c6b72045f933fbab5ee424ca",
              "status": "affected",
              "version": "624322f1adc58acd0b69f77a6ddc764207e97241",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4proc.c",
            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.6"
            },
            {
              "lessThan": "5.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "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",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.270",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.221",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: initialize copy-notify stateid before publishing it\n\nnfsd4_copy_notify() finished initializing the cpntf state after\nnfs4_alloc_init_cpntf_state() had already linked it into the\ns2s_cp_stateids IDR and the parent\u0027s sc_cp_list, with cs_count == 1 (the\nmembership reference) and none held for the caller. A racing\nOFFLOAD_CANCEL (crafted cl_id == nn-\u003es2s_cp_cl_id plus the guessable\nso_id) could reach manage_cpntf_state() and free the entry, turning the\ncaller\u0027s subsequent cpn_cnr_stateid read and cp_p_stateid/cp_p_clid\nwrites into use-after-free. The owning clientid was also only recorded\nafter publication, so it could not gate an ownership check in that window.\n\nRecord cp_p_stateid and cp_p_clid inside nfs4_alloc_init_cpntf_state()\nbefore nfs4_init_cp_state() publishes the entry, and return it with an\nextra reference. The caller reads the stateid under that reference and\ndrops it with nfs4_put_cpntf_state(); on a late error the laundromat\nreaps the entry."
        }
      ],
      "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 COPY_NOTIFY (nfsd4_copy_notify/nfs4_alloc_init_cpntf_state). NFSv4.2 COPY_NOTIFY and a racing OFFLOAD_CANCEL are processed from compounds over TCP/2049 via nfsd4_proc_compound, so a remote NFS client reaches the published cpntf object over the network.\nAC:L - The attacker controls both sides: one compound publishes the cpntf IDR entry via COPY_NOTIFY while a concurrent OFFLOAD_CANCEL uses the leaked nn-\u003es2s_cp_cl_id and a cyclic guessable so_id to kfree it before initialization finishes; the race is retryable on multiple session slots with no condition outside attacker control.\nPR:N - Default AUTH_SYS/AUTH_NULL nfsd exports do no cryptographic authentication; any host allowed by the export ACL can EXCHANGE_ID/CREATE_SESSION, OPEN a readable file, and issue COPY_NOTIFY and OFFLOAD_CANCEL. No local account or capability on the NFS server is required.\nUI:N - The attacking NFS client drives COPY_NOTIFY and the concurrent OFFLOAD_CANCEL on its own connections; no victim user or administrator action on the NFS server is required at attack time.\nS:U - The use-after-free corrupts a kmalloc\u0027d nfs4_cpntf_state in the host kernel\u0027s nfsd copy-notify tables. Impact stays in that kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - After OFFLOAD_CANCEL kfree\u0027s the object (cs_count was 1), nfsd4_copy_notify memcpy\u0027s the freed cp_stateid.cs_stid into the RPC reply; reclaim of that kmalloc slab lets the attacker disclose kernel memory. Per kernel guidance a use-after-free is C:H.\nI:H - The same path then writes cp_p_stateid and cp_p_clid into the freed nfs4_cpntf_state, a use-after-free write primitive usable for heap corruption and control-flow hijacking. Per kernel guidance a use-after-free is I:H.\nA:H - Use-after-free of nfs4_cpntf_state in an nfsd worker oopses or panics the NFS server even without full exploitation, and the attacker can repeat the concurrent RPC sequence to deny service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:50:42.637Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/863b6e995665472f2af5be2436a874ab6a9e5ac6"
        },
        {
          "url": "https://git.kernel.org/stable/c/d18d36395d973ef7372c8e6724970585f75b5c0b"
        },
        {
          "url": "https://git.kernel.org/stable/c/4415a692346a39fdb647cbd717eda510159aaf55"
        },
        {
          "url": "https://git.kernel.org/stable/c/9caad13b7cfe9ccb90cc405ac77335800e086595"
        },
        {
          "url": "https://git.kernel.org/stable/c/e08a3dcaca0505f861e344a387f37f94d95dbdc2"
        },
        {
          "url": "https://git.kernel.org/stable/c/a4d7fedcaaf33e60a01e53eafca9041ef966212f"
        },
        {
          "url": "https://git.kernel.org/stable/c/4cdef96892f4fa6e70c405b6e8f2fd6972f3b64b"
        },
        {
          "url": "https://git.kernel.org/stable/c/129643893b79f8a3c6b72045f933fbab5ee424ca"
        }
      ],
      "title": "nfsd: initialize copy-notify stateid before publishing it",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89669",
    "datePublished": "2026-09-11T19:45:55.111Z",
    "dateReserved": "2026-09-11T19:38:34.746Z",
    "dateUpdated": "2026-10-19T08:50:42.637Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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