Vulnerability-Lookup

GHSA-864V-PQ9R-VG9W

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32

Details

In the Linux kernel, the following vulnerability has been resolved:

nfsd: validate symlink target length in NFSv4 CREATE

nfsd4_decode_create() accepts an unbounded cr_datalen from the wire for NF4LNK symlink targets, allowing a client to force a kmalloc of up to the maximum RPC payload size (several MiB) per COMPOUND op that persists until compound teardown. The VFS rejects oversized targets with ENAMETOOLONG, but the allocation has already occurred.

Reject cr_datalen == 0 early with nfserr_inval and cr_datalen greater than NFS4_MAXPATHLEN (PATH_MAX) with nfserr_nametoolong to bound the allocation.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-89699"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:57Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: validate symlink target length in NFSv4 CREATE\n\nnfsd4_decode_create() accepts an unbounded cr_datalen from the wire for\nNF4LNK symlink targets, allowing a client to force a kmalloc of up to\nthe maximum RPC payload size (several MiB) per COMPOUND op that persists\nuntil compound teardown.  The VFS rejects oversized targets with\nENAMETOOLONG, but the allocation has already occurred.\n\nReject cr_datalen == 0 early with nfserr_inval and cr_datalen greater\nthan NFS4_MAXPATHLEN (PATH_MAX) with nfserr_nametoolong to bound the\nallocation.",
  "id": "GHSA-864v-pq9r-vg9w",
  "modified": "2026-09-14T15:32:34Z",
  "published": "2026-09-11T21:31:37Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89699"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/041f57056e5fb9c80adc088269322d2c61074406"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/36011308b3f01ce7dc9954f3cefcbb5291af9f95"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3ef5e7a01a4d74995a65496bc9166d1e980a4355"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/45ec115cbfecb4b3cfab7fca6f73d1b60696a25a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8661d3cb38fd148947e57dbc0871fd4d3fa33bbf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/888dad4b557352cf85be31613407b5ba51ad07d1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/895a485cd3758031ef9993c0d53cf19ce8fb4ccc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b24843ea3de1676b29902457b38507c95a80649b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-89699 (GCVE-0-2026-89699)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:46 – Updated: 2026-09-14 12:02

Title

nfsd: validate symlink target length in NFSv4 CREATE

Summary

In the Linux kernel, the following vulnerability has been resolved: nfsd: validate symlink target length in NFSv4 CREATE nfsd4_decode_create() accepts an unbounded cr_datalen from the wire for NF4LNK symlink targets, allowing a client to force a kmalloc of up to the maximum RPC payload size (several MiB) per COMPOUND op that persists until compound teardown. The VFS rejects oversized targets with ENAMETOOLONG, but the allocation has already occurred. Reject cr_datalen == 0 early with nfserr_inval and cr_datalen greater than NFS4_MAXPATHLEN (PATH_MAX) with nfserr_nametoolong to bound the allocation.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/36011308b3f01ce7d…
https://git.kernel.org/stable/c/888dad4b557352cf8…
https://git.kernel.org/stable/c/8661d3cb38fd14894…
https://git.kernel.org/stable/c/3ef5e7a01a4d74995…
https://git.kernel.org/stable/c/b24843ea3de1676b2…
https://git.kernel.org/stable/c/895a485cd3758031e…
https://git.kernel.org/stable/c/45ec115cbfecb4b3c…
https://git.kernel.org/stable/c/041f57056e5fb9c80…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 36011308b3f01ce7dc9954f3cefcbb5291af9f95 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 888dad4b557352cf85be31613407b5ba51ad07d1 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 8661d3cb38fd148947e57dbc0871fd4d3fa33bbf (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 3ef5e7a01a4d74995a65496bc9166d1e980a4355 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < b24843ea3de1676b29902457b38507c95a80649b (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 895a485cd3758031ef9993c0d53cf19ce8fb4ccc (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 45ec115cbfecb4b3cfab7fca6f73d1b60696a25a (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 041f57056e5fb9c80adc088269322d2c61074406 (git)
Linux	Linux	Affected: 2.6.12 Unaffected: 0 , < 2.6.12 (semver) Unaffected: 5.10.270 , ≤ 5.10.* (semver) Unaffected: 5.15.221 , ≤ 5.15.* (semver) Unaffected: 6.1.188 , ≤ 6.1.* (semver) Unaffected: 6.6.157 , ≤ 6.6.* (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)

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4xdr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "36011308b3f01ce7dc9954f3cefcbb5291af9f95",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "888dad4b557352cf85be31613407b5ba51ad07d1",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "8661d3cb38fd148947e57dbc0871fd4d3fa33bbf",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "3ef5e7a01a4d74995a65496bc9166d1e980a4355",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "b24843ea3de1676b29902457b38507c95a80649b",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "895a485cd3758031ef9993c0d53cf19ce8fb4ccc",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
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              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "lessThan": "2.6.12",
              "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-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.270",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.221",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "2.6.12",
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                {
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                  "versionEndExcluding": "6.18.50",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: validate symlink target length in NFSv4 CREATE\n\nnfsd4_decode_create() accepts an unbounded cr_datalen from the wire for\nNF4LNK symlink targets, allowing a client to force a kmalloc of up to\nthe maximum RPC payload size (several MiB) per COMPOUND op that persists\nuntil compound teardown.  The VFS rejects oversized targets with\nENAMETOOLONG, but the allocation has already occurred.\n\nReject cr_datalen == 0 early with nfserr_inval and cr_datalen greater\nthan NFS4_MAXPATHLEN (PATH_MAX) with nfserr_nametoolong to bound the\nallocation."
        }
      ],
      "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 reached through the in-kernel NFS server (nfsd) when a remote client sends an NFSv4 COMPOUND containing OP_CREATE of type NF4LNK over TCP/UDP port 2049; nfsd4_decode_create() runs during XDR decode of that compound.\nAC:L - A client fully controls cr_datalen on the wire; one COMPOUND with an NF4LNK target larger than PATH_MAX but within the RPC payload deterministically forces svcxdr_dupstr()/kmalloc of that size, with no race or attacker-uncontrollable condition.\nPR:N - The oversized kmalloc occurs in nfsd4_decode_compound() before SEQUENCE/session checks, PUTFH, fh_verify(), or export flavor enforcement; AUTH_NULL and AUTH_UNIX are accepted at the RPC layer, so an unauthenticated peer that can reach nfsd needs no host credentials.\nUI:N - Exploitation requires only attacker-sent NFSv4 COMPOUND RPCs; no administrator or end-user action on the server is needed beyond nfsd already listening.\nS:U - Impact is confined to kernel memory consumption on the NFS server within the same security authority; there is no VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:N - The defect only copies attacker-supplied symlink-target bytes into a correctly sized kmalloc buffer; there is no out-of-bounds read, use-after-free, or other disclosure primitive.\nI:N - There is no memory corruption or attacker-controlled write; the buffer is sized to cr_datalen and is only a temporary copy that filesystems later reject with ENAMETOOLONG.\nA:H - Each COMPOUND can force a GFP_KERNEL kmalloc of up to the maximum RPC payload (several MiB) on an nfsd thread until compound teardown; flooding concurrent requests across nfsd threads can exhaust kernel memory and OOM or stall the host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-14T12:02:05.331Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/36011308b3f01ce7dc9954f3cefcbb5291af9f95"
        },
        {
          "url": "https://git.kernel.org/stable/c/888dad4b557352cf85be31613407b5ba51ad07d1"
        },
        {
          "url": "https://git.kernel.org/stable/c/8661d3cb38fd148947e57dbc0871fd4d3fa33bbf"
        },
        {
          "url": "https://git.kernel.org/stable/c/3ef5e7a01a4d74995a65496bc9166d1e980a4355"
        },
        {
          "url": "https://git.kernel.org/stable/c/b24843ea3de1676b29902457b38507c95a80649b"
        },
        {
          "url": "https://git.kernel.org/stable/c/895a485cd3758031ef9993c0d53cf19ce8fb4ccc"
        },
        {
          "url": "https://git.kernel.org/stable/c/45ec115cbfecb4b3cfab7fca6f73d1b60696a25a"
        },
        {
          "url": "https://git.kernel.org/stable/c/041f57056e5fb9c80adc088269322d2c61074406"
        }
      ],
      "title": "nfsd: validate symlink target length in NFSv4 CREATE",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89699",
    "datePublished": "2026-09-11T19:46:17.293Z",
    "dateReserved": "2026-09-11T19:38:34.750Z",
    "dateUpdated": "2026-09-14T12:02:05.331Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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