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CVE-2026-89697 (GCVE-0-2026-89697)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:46 – Updated: 2026-09-13 06:33
VLAI
Title
nfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr()
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr() The BOTH_TIME_SET branch calls fh_verify() early so setattr_prepare() can inspect the dentry. This causes nfsd_setattr() to skip fh_want_write(), so notify_change() runs without a mount write reference. Add the missing fh_want_write() call after the early fh_verify().
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: cc265089ce1b176dde963c74b53593446ee7f99a , < 15ca3b64a69caa6194bed8f98a20ed90a11c11dd (git)
Affected: cc265089ce1b176dde963c74b53593446ee7f99a , < 533964d420d385e11b08dd4c56c66ef5dcccaf08 (git)
Affected: cc265089ce1b176dde963c74b53593446ee7f99a , < c4a409b86a92815181a8e9395c6bf1696ad19175 (git)
Affected: cc265089ce1b176dde963c74b53593446ee7f99a , < 4e475be769aa9f7a2c1ce55a2b8592cfccacddcc (git)
Affected: 1cb57d81cf20fe24b9e2e1daf57bfbdc24b77cd8 (git)
Affected: 3.18.46 , < 3.19 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 4.2
Unaffected: 0 , < 4.2 (semver)
Unaffected: 6.12.109 , ≤ 6.12.* (semver)
Unaffected: 6.18.50 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfsproc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "cc265089ce1b176dde963c74b53593446ee7f99a",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "cc265089ce1b176dde963c74b53593446ee7f99a",
              "versionType": "git"
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            {
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              "status": "affected",
              "version": "cc265089ce1b176dde963c74b53593446ee7f99a",
              "versionType": "git"
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              "status": "affected",
              "version": "cc265089ce1b176dde963c74b53593446ee7f99a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1cb57d81cf20fe24b9e2e1daf57bfbdc24b77cd8",
              "versionType": "git"
            },
            {
              "lessThan": "3.19",
              "status": "affected",
              "version": "3.18.46",
              "versionType": "semver"
            }
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        {
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          "product": "Linux",
          "programFiles": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "4.2"
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              "status": "unaffected",
              "version": "0",
              "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-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "3.18.46",
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                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr()\n\nThe BOTH_TIME_SET branch calls fh_verify() early so setattr_prepare()\ncan inspect the dentry. This causes nfsd_setattr() to skip\nfh_want_write(), so notify_change() runs without a mount write\nreference.\n\nAdd the missing fh_want_write() call after the early fh_verify()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is in nfsd_proc_setattr(), the in-kernel NFSv2 SETATTR handler. A remote client reaches it by sending an NFSv2 SETATTR RPC over TCP/UDP port 2049 with both atime and mtime set, so no local access to the server is required.\nAC:L - Crafting SETATTR with ATTR_ATIME_SET|ATTR_MTIME_SET and equal timestamps deterministically takes the early fh_verify() path so nfsd_setattr() skips fh_want_write(). The attacker fully controls the RPC; no race or uninfluenced memory layout is required.\nPR:N - Default nfsd exports accept AUTH_SYS and AUTH_NULL with no cryptographic authentication, so the client asserts uid/gid. Any host permitted by the export list can issue SETATTR; this matches prior nfsd CNA scoring as PR:N.\nUI:N - The attacking NFS client issues the SETATTR RPC itself. No administrator or end-user action on the server is required.\nS:U - notify_change() without a mount write reference affects only the exported filesystem in the same kernel security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:N - The defect is a missing mnt_want_write()/sb_start_write() around notify_change() and commit_metadata(). It does not leak kernel memory, pointers, or file contents beyond ordinary authorized NFS access.\nI:H - nfsd_permission\u0027s read-only check does not cover freeze state, so SETATTR including ATTR_SIZE truncate, mode, and ownership updates proceeds on a frozen export and in a remount-ro race, letting a client mutate files and corrupt snapshots when writes should be blocked.\nA:H - Skipping freeze protection lets setattr run during fsfreeze, which can deadlock (inode_lock versus sb_start_write ordering), trigger filesystem withdraw/asserts such as GFS2 adding buffers while frozen, and hang or crash the nfsd thread."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:33:21.070Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/15ca3b64a69caa6194bed8f98a20ed90a11c11dd"
        },
        {
          "url": "https://git.kernel.org/stable/c/533964d420d385e11b08dd4c56c66ef5dcccaf08"
        },
        {
          "url": "https://git.kernel.org/stable/c/c4a409b86a92815181a8e9395c6bf1696ad19175"
        },
        {
          "url": "https://git.kernel.org/stable/c/4e475be769aa9f7a2c1ce55a2b8592cfccacddcc"
        }
      ],
      "title": "nfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr()",
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        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89697",
    "datePublished": "2026-09-11T19:46:15.772Z",
    "dateReserved": "2026-09-11T19:38:34.750Z",
    "dateUpdated": "2026-09-13T06:33:21.070Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-89697",
      "date": "2026-09-13",
      "epss": "0.00603",
      "percentile": "0.46984"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-89697\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-09-11T20:19:56.843\",\"lastModified\":\"2026-09-13T07:17:35.480\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr()\\n\\nThe BOTH_TIME_SET branch calls fh_verify() early so setattr_prepare()\\ncan inspect the dentry. This causes nfsd_setattr() to skip\\nfh_want_write(), so notify_change() runs without a mount write\\nreference.\\n\\nAdd the missing fh_want_write() call after the early fh_verify().\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/nfsd/nfsproc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"cc265089ce1b176dde963c74b53593446ee7f99a\",\"lessThan\":\"15ca3b64a69caa6194bed8f98a20ed90a11c11dd\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cc265089ce1b176dde963c74b53593446ee7f99a\",\"lessThan\":\"533964d420d385e11b08dd4c56c66ef5dcccaf08\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cc265089ce1b176dde963c74b53593446ee7f99a\",\"lessThan\":\"c4a409b86a92815181a8e9395c6bf1696ad19175\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cc265089ce1b176dde963c74b53593446ee7f99a\",\"lessThan\":\"4e475be769aa9f7a2c1ce55a2b8592cfccacddcc\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"1cb57d81cf20fe24b9e2e1daf57bfbdc24b77cd8\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3.18.46\",\"lessThan\":\"3.19\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/nfsd/nfsproc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.2\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.2\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.109\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.50\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H\",\"baseScore\":9.1,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.2}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/15ca3b64a69caa6194bed8f98a20ed90a11c11dd\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4e475be769aa9f7a2c1ce55a2b8592cfccacddcc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/533964d420d385e11b08dd4c56c66ef5dcccaf08\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c4a409b86a92815181a8e9395c6bf1696ad19175\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-09-13T06:52:17+00:00",
      "cve": "CVE-2026-89697",
      "id": "CVE-2026-89697",
      "initial_release_date": "2026-09-11T19:46:15.772000+00:00",
      "product_status:known_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: NFS daemon bypasses write verification during attribute setting",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89697.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-12T16:23:31Z",
      "cve": "CVE-2026-89697",
      "id": "CVE-2026-89697",
      "initial_release_date": "2026-09-12T16:23:31Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89697",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89697.json",
      "version": "2"
    }
  }
}



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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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