Vulnerability-Lookup

FKIE_CVE-2026-89682

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-09-13 07:17

Severity

8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net nfsd_file_dispose_list_delayed() defers fput() to nfsd service threads via a per-net freeme queue, preventing the shrinker and GC worker from bearing the cost of closing files (see ffb402596147). However, the queue lives in a separately-allocated struct nfsd_fcache_disposal that is freed by nfsd_free_fcache_disposal_net() during per-net teardown. The global shrinker, laundrette, and fsnotify callbacks can still be inside nfsd_file_dispose_list_delayed() dereferencing that pointer, causing a use-after-free. Inline the spinlock and freeme list directly into struct nfsd_net (as fcache_dispose_lock and fcache_dispose_list), eliminating the separately allocated struct nfsd_fcache_disposal entirely. These fields now have the same lifetime as the net namespace itself, so there is no dangling pointer to chase. nfsd_file_cache_start_net() now just initializes the inline fields and cannot fail due to allocation. nfsd_file_cache_shutdown_net() drains the inline list directly instead of freeing a separate struct. The alloc/free helpers are removed.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ba0ee9e04b7a0356c28d5a2fe445db675d24e572
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/cadc9036d5a8209f89e7026ddba7cfb1c716b03c

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/filecache.c",
            "fs/nfsd/netns.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ba0ee9e04b7a0356c28d5a2fe445db675d24e572",
              "status": "affected",
              "version": "1463b38e7cf34d4cc60f41daff459ad807b2e408",
              "versionType": "git"
            },
            {
              "lessThan": "cadc9036d5a8209f89e7026ddba7cfb1c716b03c",
              "status": "affected",
              "version": "1463b38e7cf34d4cc60f41daff459ad807b2e408",
              "versionType": "git"
            },
            {
              "lessThan": "bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4",
              "status": "affected",
              "version": "1463b38e7cf34d4cc60f41daff459ad807b2e408",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e8f923e1e9fcc0832a12c8a2461792e5a9544c03",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3bc94fb44f10ef852723e1aeaac6794c5ab16aec",
              "versionType": "git"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.220",
              "versionType": "semver"
            },
            {
              "lessThan": "5.16",
              "status": "affected",
              "version": "5.15.154",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/filecache.c",
            "fs/nfsd/netns.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.17"
            },
            {
              "lessThan": "5.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "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"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net\n\nnfsd_file_dispose_list_delayed() defers fput() to nfsd service threads\nvia a per-net freeme queue, preventing the shrinker and GC worker from\nbearing the cost of closing files (see ffb402596147).  However, the\nqueue lives in a separately-allocated struct nfsd_fcache_disposal that\nis freed by nfsd_free_fcache_disposal_net() during per-net teardown.\nThe global shrinker, laundrette, and fsnotify callbacks can still be\ninside nfsd_file_dispose_list_delayed() dereferencing that pointer,\ncausing a use-after-free.\n\nInline the spinlock and freeme list directly into struct nfsd_net (as\nfcache_dispose_lock and fcache_dispose_list), eliminating the separately\nallocated struct nfsd_fcache_disposal entirely.  These fields now have\nthe same lifetime as the net namespace itself, so there is no dangling\npointer to chase.\n\nnfsd_file_cache_start_net() now just initializes the inline fields and\ncannot fail due to allocation.  nfsd_file_cache_shutdown_net() drains\nthe inline list directly instead of freeing a separate struct.  The\nalloc/free helpers are removed."
    }
  ],
  "id": "CVE-2026-89682",
  "lastModified": "2026-09-13T07:17:34.003",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-11T20:19:55.043",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ba0ee9e04b7a0356c28d5a2fe445db675d24e572"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cadc9036d5a8209f89e7026ddba7cfb1c716b03c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-89682 (GCVE-0-2026-89682)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:46 – Updated: 2026-09-13 06:33

Title

nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net

Summary

Severity

8.1 (High)


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

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/ba0ee9e04b7a0356c…
https://git.kernel.org/stable/c/cadc9036d5a8209f8…
https://git.kernel.org/stable/c/bbf13732f74351d21…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1463b38e7cf34d4cc60f41daff459ad807b2e408 , < ba0ee9e04b7a0356c28d5a2fe445db675d24e572 (git) Affected: 1463b38e7cf34d4cc60f41daff459ad807b2e408 , < cadc9036d5a8209f89e7026ddba7cfb1c716b03c (git) Affected: 1463b38e7cf34d4cc60f41daff459ad807b2e408 , < bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4 (git) Affected: e8f923e1e9fcc0832a12c8a2461792e5a9544c03 (git) Affected: 3bc94fb44f10ef852723e1aeaac6794c5ab16aec (git) Affected: 5.10.220 , < 5.11 (semver) Affected: 5.15.154 , < 5.16 (semver)
Linux	Linux	Affected: 5.17 Unaffected: 0 , < 5.17 (semver) Unaffected: 6.18.51 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/filecache.c",
            "fs/nfsd/netns.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ba0ee9e04b7a0356c28d5a2fe445db675d24e572",
              "status": "affected",
              "version": "1463b38e7cf34d4cc60f41daff459ad807b2e408",
              "versionType": "git"
            },
            {
              "lessThan": "cadc9036d5a8209f89e7026ddba7cfb1c716b03c",
              "status": "affected",
              "version": "1463b38e7cf34d4cc60f41daff459ad807b2e408",
              "versionType": "git"
            },
            {
              "lessThan": "bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4",
              "status": "affected",
              "version": "1463b38e7cf34d4cc60f41daff459ad807b2e408",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e8f923e1e9fcc0832a12c8a2461792e5a9544c03",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3bc94fb44f10ef852723e1aeaac6794c5ab16aec",
              "versionType": "git"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.220",
              "versionType": "semver"
            },
            {
              "lessThan": "5.16",
              "status": "affected",
              "version": "5.15.154",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/filecache.c",
            "fs/nfsd/netns.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.17"
            },
            {
              "lessThan": "5.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "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": "6.18.51",
                  "versionStartIncluding": "5.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "5.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "5.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.10.220",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.15.154",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net\n\nnfsd_file_dispose_list_delayed() defers fput() to nfsd service threads\nvia a per-net freeme queue, preventing the shrinker and GC worker from\nbearing the cost of closing files (see ffb402596147).  However, the\nqueue lives in a separately-allocated struct nfsd_fcache_disposal that\nis freed by nfsd_free_fcache_disposal_net() during per-net teardown.\nThe global shrinker, laundrette, and fsnotify callbacks can still be\ninside nfsd_file_dispose_list_delayed() dereferencing that pointer,\ncausing a use-after-free.\n\nInline the spinlock and freeme list directly into struct nfsd_net (as\nfcache_dispose_lock and fcache_dispose_list), eliminating the separately\nallocated struct nfsd_fcache_disposal entirely.  These fields now have\nthe same lifetime as the net namespace itself, so there is no dangling\npointer to chase.\n\nnfsd_file_cache_start_net() now just initializes the inline fields and\ncannot fail due to allocation.  nfsd_file_cache_shutdown_net() drains\nthe inline list directly instead of freeing a separate struct.  The\nalloc/free helpers are removed."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - nfsd_file_dispose_list_delayed() runs in the in-kernel NFS server filecache on nfsd_files cached from remote OPEN/READ/WRITE over TCP/UDP 2049; a network NFS client populates that cache and can drive delayed dispose via the global GC laundrette, shrinker, or fsnotify from REMOVE, matching kernel guidance that nfsd is Network.\nAC:H - The UAF requires nfsd_free_fcache_disposal_net() to kfree the separately allocated per-net nfsd_fcache_disposal during nfsd_file_cache_shutdown_net() while the global shrinker, laundrette, or fsnotify still dereference it\u2014a victim-side nfsd restart, shutdown, or netns teardown the remote attacker cannot cause, only race against.\nPR:N - Typical nfsd deployments use AUTH_SYS/AUTH_NULL with IP-based exports, so a remote peer that can reach the export self-asserts credentials with no cryptographic authentication and can OPEN/READ files into the filecache; no local Linux account or capability is required.\nUI:N - The attacker issues NFS operations that populate and reclaim the filecache themselves; nfsd per-net teardown is an environmental race counted under Attack Complexity, not an interactive victim action such as mounting a filesystem or opening a file.\nS:U - The use-after-free corrupts host-kernel slab (struct nfsd_fcache_disposal) within the same OS security authority as nfsd and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - This is a slab use-after-free of the kmalloc\u0027d nfsd_fcache_disposal object; reclaim or spray of the freed object lets dispose_list_delayed read attacker-controlled lock and list_head fields, enabling arbitrary kernel disclosure per UAF guidance.\nI:H - spin_lock and list_move_tail on the freed disposal object write into reclaimed slab, corrupting list nodes and lock state and yielding a groomable write or control-flow hijack primitive characteristic of exploitable kernel UAFs.\nA:H - Use-after-free of the disposal spinlock and list from shrinker, GC worker, or fsnotify context causes kernel oops, panic, or list-corruption hangs, fully disrupting availability of the NFS server host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:33:06.103Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ba0ee9e04b7a0356c28d5a2fe445db675d24e572"
        },
        {
          "url": "https://git.kernel.org/stable/c/cadc9036d5a8209f89e7026ddba7cfb1c716b03c"
        },
        {
          "url": "https://git.kernel.org/stable/c/bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4"
        }
      ],
      "title": "nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89682",
    "datePublished": "2026-09-11T19:46:04.882Z",
    "dateReserved": "2026-09-11T19:38:34.748Z",
    "dateUpdated": "2026-09-13T06:33:06.103Z",
    "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.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.