{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-89696",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-89696",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-09-11T19:46:15.030Z",
    "updatedAt": "2026-10-19T08:51:09.479Z",
    "importedAt": "2026-10-24T01:58:35.090Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "nfsd: block non-SAVEFH ops after FOREIGN PUTFH to prevent NULL deref",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: block non-SAVEFH ops after FOREIGN PUTFH to prevent NULL deref\n\nWhen CONFIG_NFSD_V4_2_INTER_SSC is enabled, nfsd4_putfh() can return\nsuccess with fh_dentry and fh_export both NULL if fh_verify() returns\nnfserr_stale and putfh->no_verify is true. The NFSD4_FH_FOREIGN flag\nis set, but the compound dispatch loop only uses this flag to bypass\nthe nfserr_nofilehandle check -- it does not prevent subsequent ops\nfrom running with a NULL fh_dentry.\n\nA remote client can exploit this by crafting a COMPOUND that includes\nan inter-SSC COPY (which causes check_if_stalefh_allowed() to set\nno_verify=true on the saved PUTFH) with an additional op inserted\nbetween the source PUTFH and SAVEFH. For example, SETATTR calls\nfh_want_write() which dereferences fh_export->ex_path.mnt without\ncalling fh_verify() first, causing a NULL pointer dereference in the\nnfsd kthread.\n\nFix this by gating the dispatch loop: when NFSD4_FH_FOREIGN is set\nand fh_dentry is NULL, only OP_SAVEFH (needed for the inter-SSC flow)\nand ops with ALLOWED_WITHOUT_FH (which don't need a resolved\nfilehandle) may proceed. All other ops receive nfserr_stale, per\nRFC 7862 Section 15.2.3 which specifies that foreign filehandle\nvalidation is deferred to the consuming operation and NFS4ERR_STALE\nreturned at that point.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "b9e8638e3d9ed8334f1f7071e081860aac37e83e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "ffdc844e673d2bcb2af8c8c3eef8cdea59d0bf32"
            },
            {
              "version": "b9e8638e3d9ed8334f1f7071e081860aac37e83e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "00c84f4eec715e501efc080a5670114189e42507"
            },
            {
              "version": "b9e8638e3d9ed8334f1f7071e081860aac37e83e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "2d9846fd1c767920fddd4bde30eb35cd2969df13"
            },
            {
              "version": "b9e8638e3d9ed8334f1f7071e081860aac37e83e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "977e6f006a7a3ffc4216ae6034f768f8de6fd138"
            },
            {
              "version": "b9e8638e3d9ed8334f1f7071e081860aac37e83e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "35f248bd40b47b229d4999581df45b97daadd977"
            },
            {
              "version": "b9e8638e3d9ed8334f1f7071e081860aac37e83e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "311f7d926630940650447cbd1c932b076b40a6c4"
            },
            {
              "version": "b9e8638e3d9ed8334f1f7071e081860aac37e83e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "bf4d338dc8625d70c7f2cb0657d66851a7ac9154"
            },
            {
              "version": "b9e8638e3d9ed8334f1f7071e081860aac37e83e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "c59738a00aa51b16adc1b5ceb7c80877168efb4d"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "5.6",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "5.6"
            },
            {
              "version": "5.10.270",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.15.221",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.188",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.157",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.109",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.18.50",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "version": "7.2.4",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "version": "7.3",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}