{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-89679",
  "modified": "2026-10-07T14:35:31Z",
  "upstream": [
    "CVE-2026-89679"
  ],
  "published": "2026-09-11T19:47:07Z",
  "summary": "nfsd: fix null dereference in nfsd4_setattr for deleg timestamp attrs",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix null dereference in nfsd4_setattr for deleg timestamp attrs\n\nWhen a SETATTR request includes FATTR4_WORD2_TIME_DELEG_ACCESS or\nFATTR4_WORD2_TIME_DELEG_MODIFY in the attribute bitmap, nfsd4_setattr()\nsets deleg_attrs=true and calls nfs4_preprocess_stateid_op() to validate\nthe stateid.\n\nIf the client supplies the NFSv4 \"one stateid\" (all-0xFF bytes),\ncheck_special_stateids() returns nfs_ok without populating the output\nnfs4_stid pointer, because the special-stateid path in\nnfs4_preprocess_stateid_op() jumps to done: with s==NULL, and the\n\"if (s)\" block that would set *cstid is skipped. The local variable `st`\nremains NULL.\n\nBack in nfsd4_setattr(), the if (deleg_attrs) block then unconditionally\ndereferences st->sc_type (at offset 4 from NULL), causing a kernel oops.\n\nThis is remotely triggerable by any NFSv4 client: send COMPOUND [PUTROOTFH,\nSETATTR(ONE_STATEID, {bmval2=FATTR4_WORD2_TIME_DELEG_ACCESS, ...})].\nNo authentication, delegation, or prior state is required.\n\nFix by adding a NULL check before the dereference. A special stateid is\nnot a delegation stateid, so the existing nfserr_bad_stateid return value\nis already correct; we only need to guard the pointer dereference itself.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:13",
        "name": "linux"
      },
      "versions": [
        "1:6.18.29-1+rpt1",
        "1:6.18.33-1+rpt1",
        "1:6.18.34-1+rpt1",
        "1:6.18.39-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.18.29+rpt-rpi-2712",
            "binary_version": "1:6.18.29-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.29+rpt-rpi-v6",
            "binary_version": "1:6.18.29-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.29+rpt-rpi-v7",
            "binary_version": "1:6.18.29-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.29+rpt-rpi-v8",
            "binary_version": "1:6.18.29-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.29+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.29-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-2712",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v6",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v7",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v8",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-2712",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v6",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v7",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v8",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-2712",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v6",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v7",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v8",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.39-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.18.29-1+rpt1": {
            "linux_commit": "66318c5b5cd8145a662303af12ed39ac07eb27cc",
            "upstream_version": "6.18.29",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.50"
          },
          "1:6.18.33-1+rpt1": {
            "linux_commit": "95b85bebbedcaedfa7ca79116ed38b7376fba412",
            "upstream_version": "6.18.33",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.50"
          },
          "1:6.18.34-1+rpt1": {
            "linux_commit": "c8c7494100e99ee05b11aaa4f0588a223a63d1af",
            "upstream_version": "6.18.34",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.50"
          },
          "1:6.18.39-1+rpt1": {
            "linux_commit": "60ea684a8ace97bb0db1a16e20753bdd6ab371ff",
            "upstream_version": "6.18.39",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.50"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-89679"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3c5119b799a7f57db332b2c31e806de16c869f0f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3c896db123892256fd39af0ee8c2d02c63539983"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fe456c8c0931bb3e8a03d429920e87fd85747fba"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-13T06:49:25Z"
  }
}