nfsd: revoke copy-notify stateids before dropping their reference

{
  "id": "28b9405c0882eb3ee2a9b6b315ba33367e4672be50b11fe7268dc903f3a29114",
  "url": "https://osv.dev/vulnerability/CVE-2026-89663",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "nfsd: revoke copy-notify stateids before dropping their reference",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: nfsd: revoke copy-notify stateids before dropping their reference Copy-notify stateids live in the s2s_cp_stateids IDR and on their parent stid's sc_cp_list, pinned by a single membership reference. _free_cpntf_state_locked() only unlinks an entry once its refcount reaches zero, so any revoke path that runs while a concurrent find_cpntf_state()/manage_cpntf_state() holder has elevated cs_count drops the reference without unlinking, leaving the entry discoverable with its membership reference already consumed. A second revoke or a laundromat tick then frees it while the reader still holds the pointer -- a KASAN-detectable use-after-free at the reader's nfs4_put_cpntf_state(). This affected all three revoke paths: - The parent-stid drain (nfs4_free_cpntf_statelist()) repeatedly called _free_cpntf_state_locked() on the first list entry; a holder that had bumped cs_count made it return early, so the next iteration re-decremented and burned the holder's reference. - OFFLOAD_CANCEL (manage_cpntf_state()) and laundromat expiry likewise used _free_cpntf_state_locked() and could drop 2->1 without unlinking. Add revoke_cpntf_state_locked(), which unhashes the entry from the IDR and sc_cp_list first (deferring the final free to any holder), and use it from all three revoke paths. The drain now walks with list_for_each_entry_safe() and revokes each entry unconditionally, so it terminates in one pass per entry regardless ",
    "evidence": "osv:CVE-2026-89663",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.270",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.221",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.188",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.109",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.50",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-89663",
      "aliases": [
        "CVE-2026-89663"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "5f00e0ab4de45d4f9e4bd0883cf2517acf63fc0d"
                },
                {
                  "fixed": "06a62f6dbc60791f4229c6950b1eec6b18df9af1"
                },
                {
                  "fixed": "a1fca0f7bbb7b100a39c7ba8dd7922c87c4237a3"
                },
                {
                  "fixed": "caddbeffab1eaba1d2bcf5ceda35547863466705"
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                {
                  "fixed": "6b8149448cdcb476fba4559d1ecc247efee9971b"
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                {
                  "fixed": "b56d2c5f01cddbeca7d11cce81d97db4ec9a464f"
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                {
                  "fixed": "ff8a3cff02b92b2a82f1a9876038fcf953ae9c25"
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                  "fixed": "3b0c3595db99bb4bebd7c8aa8a36f3c50e411bb7"
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            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89663.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.6.0"
                },
                {
                  "fixed": "5.10.270"
                }
              ]
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            {
              "type": "ECOSYSTEM",
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                  "introduced": "5.11.0"
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                  "introduced": "6.7.0"
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              "type": "ECOSYSTEM",
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                  "introduced": "6.13.0"
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                {
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            {
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89663.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:36.786576787Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/06a62f6dbc60791f4229c6950b1eec6b18df9af1",
        "https://git.kernel.org/stable/c/3b0c3595db99bb4bebd7c8aa8a36f3c50e411bb7",
        "https://git.kernel.org/stable/c/5f00e0ab4de45d4f9e4bd0883cf2517acf63fc0d",
        "https://git.kernel.org/stable/c/6b8149448cdcb476fba4559d1ecc247efee9971b",
        "https://git.kernel.org/stable/c/a1fca0f7bbb7b100a39c7ba8dd7922c87c4237a3",
        "https://git.kernel.org/stable/c/b56d2c5f01cddbeca7d11cce81d97db4ec9a464f",
        "https://git.kernel.org/stable/c/caddbeffab1eaba1d2bcf5ceda35547863466705",
        "https://git.kernel.org/stable/c/ff8a3cff02b92b2a82f1a9876038fcf953ae9c25",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89663.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89663",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89663.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-89663",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 504033,
  "published_at": "2026-09-11T19:45:50.577+00:00"
}