CVE-2026-89684 (GCVE-0-2026-89684)
Vulnerability from cvelistv5
Published
2026-09-11 19:46
Modified
2026-10-19 08:50
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix cpntf publish race in nfs4_init_cp_state nfs4_alloc_init_cpntf_state() published the new cpntf entry into the s2s_cp_stateids IDR (with cs_type set) in one s2s_cp_lock section, then took the lock again to list_add() it onto p_stid->sc_cp_list. In the gap the entry is reachable by so_id but cp_list is still {NULL,NULL} from kzalloc. A racing OFFLOAD_CANCEL (so_id is echoed to the client as cnr_stateid, so any NFSv4.2 client can drive it) reaches manage_cpntf_state() -> _free_cpntf_state_locked() and does list_del() on the zeroed list_head, oopsing the server. Fold the cs_type assignment and the list_add() into the same critical section as idr_alloc_cyclic(), so a concurrent lookup either misses the entry or sees a fully linked cp_list. INIT_LIST_HEAD() the entry after allocation and switch _free_cpntf_state_locked() to list_del_init() so a stale unlink is a no-op. nfs4_init_copy_state() passes NULL p_stid and skips the list_add, preserving NFS4_COPY_STID semantics.
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/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "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": "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: fix cpntf publish race in nfs4_init_cp_state\n\nnfs4_alloc_init_cpntf_state() published the new cpntf entry into the\ns2s_cp_stateids IDR (with cs_type set) in one s2s_cp_lock section, then\ntook the lock again to list_add() it onto p_stid-\u003esc_cp_list. In the gap\nthe entry is reachable by so_id but cp_list is still {NULL,NULL} from\nkzalloc. A racing OFFLOAD_CANCEL (so_id is echoed to the client as\ncnr_stateid, so any NFSv4.2 client can drive it) reaches\nmanage_cpntf_state() -\u003e _free_cpntf_state_locked() and does list_del() on\nthe zeroed list_head, oopsing the server.\n\nFold the cs_type assignment and the list_add() into the same critical\nsection as idr_alloc_cyclic(), so a concurrent lookup either misses the\nentry or sees a fully linked cp_list. INIT_LIST_HEAD() the entry after\nallocation and switch _free_cpntf_state_locked() to list_del_init() so a\nstale unlink is a no-op. nfs4_init_copy_state() passes NULL p_stid and\nskips the list_add, preserving NFS4_COPY_STID semantics."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The flaw is in nfsd NFSv4.2 COPY_NOTIFY/OFFLOAD_CANCEL (nfsd4_copy_notify, nfs4_alloc_init_cpntf_state, manage_cpntf_state). Compounds reach nfsd4_proc_compound via svc_process on TCP/2049, so a remote NFS client triggers the published cpntf IDR entry over the network.\nAC:L - The attacker drives both sides: COPY_NOTIFY publishes the cpntf into s2s_cp_stateids while a concurrent OFFLOAD_CANCEL uses the leaked s2s_cp_cl_id and cyclic so_id to list_del the still-zeroed cp_list. The window is retryable on multiple session slots with no victim-controlled state.\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 sends COPY_NOTIFY and the concurrent OFFLOAD_CANCEL itself; no victim user or administrator action on the NFS server is required at attack time.\nS:U - list_del of the uninitialized cp_list oopses an nfsd worker in the host kernel copy-notify tables. Impact stays in that kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:N - The race is list_del on a kzalloc\u0027d nfs4_cpntf_state.cp_list still {NULL,NULL}, a NULL-pointer dereference in __list_del. It oopses without reading kernel memory or providing an information-disclosure primitive.\nI:N - The only write is next-\u003eprev/prev-\u003enext through NULL list pointers from kzalloc; a remote NFS client cannot map the NULL page, so this is not a kernel write or control-flow hijack primitive.\nA:H - list_del on the zeroed list_head oopses or panics the nfsd thread (and can leak s2s_cp_lock). The attacker can repeat the concurrent COMPOUND sequence to deny NFS service and take down the server."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:50:57.622Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/63e18fc65587fd3f7b4c6d70e96d32fc41d82ba3"
        },
        {
          "url": "https://git.kernel.org/stable/c/6ac469a274e3c7d87fc46ba46d83b95009680407"
        },
        {
          "url": "https://git.kernel.org/stable/c/8eeca993357a0bc35aaefebfd7462ac7b0a21d9a"
        },
        {
          "url": "https://git.kernel.org/stable/c/bfeac42d9074e539bacd1898dd8c14b7f5776620"
        },
        {
          "url": "https://git.kernel.org/stable/c/21d6c5957f5ca97d7352e60f55ea412beb9419f5"
        },
        {
          "url": "https://git.kernel.org/stable/c/a631a26a8777bb235eabd478bbbaf26a4db750bf"
        },
        {
          "url": "https://git.kernel.org/stable/c/c7270f62e7a05a2ee68aa2b74262b658a14463bd"
        },
        {
          "url": "https://git.kernel.org/stable/c/be3a5c1d857b0dcbc11796cea603ef25834f75b2"
        }
      ],
      "title": "nfsd: fix cpntf publish race in nfs4_init_cp_state",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89684",
    "datePublished": "2026-09-11T19:46:06.374Z",
    "dateReserved": "2026-09-11T19:38:34.748Z",
    "dateUpdated": "2026-10-19T08:50:57.622Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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