FKIE_CVE-2026-53399

Vulnerability from fkie_nvd - Published: 2026-07-19 12:16 - Updated: 2026-07-20 15:16
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: release layout stid on setlease failure nfs4_alloc_stid() publishes the new stid into cl->cl_stateids via idr_alloc_cyclic() under cl_lock before returning to nfsd4_alloc_layout_stateid(). When nfsd4_layout_setlease() then fails, the error path frees the layout stateid directly with kmem_cache_free() without ever calling idr_remove(), leaving the IDR slot pointing at freed slab memory. Any subsequent IDR walker (states_show, client teardown) dereferences the dangling pointer. The correct teardown for an IDR-published stid is nfs4_put_stid(), which removes the IDR slot under cl_lock, dispatches sc_free (nfsd4_free_layout_stateid) to release ls->ls_file via nfsd4_close_layout(), and drops the nfs4_file reference in its tail. A second issue blocks that switch: nfsd4_free_layout_stateid() unconditionally inspects ls->ls_fence_work via delayed_work_pending() under ls_lock, but INIT_DELAYED_WORK(&ls->ls_fence_work, ...) currently runs only after the setlease call. On the setlease-failure path the destructor would touch an uninitialized delayed_work. nfsd4_alloc_layout_stateid() nfs4_alloc_stid() /* idr_alloc_cyclic under cl_lock */ nfsd4_layout_setlease() /* fails */ nfs4_put_stid() nfsd4_free_layout_stateid() delayed_work_pending(&ls->ls_fence_work) /* needs INIT */ nfsd4_close_layout() /* nfsd_file_put(ls->ls_file) */ put_nfs4_file() Fix by hoisting the ls_fenced / ls_fence_delay / INIT_DELAYED_WORK initialization above the nfsd4_layout_setlease() call, and replace the manual nfsd_file_put + put_nfs4_file + kmem_cache_free cleanup with a single nfs4_put_stid(stp).
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/30d55c8aabb261bc3f427d6b9aae7ef6206063f9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/83c2b7797742339bb768f83935f7ca33950db138
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8dee7c278f1c2b5bb80e17a6281c3812fc8b0cdd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d369e5edfaaf83a448016e2f1da392b2174be801
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4layouts.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d369e5edfaaf83a448016e2f1da392b2174be801",
              "status": "affected",
              "version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
              "versionType": "git"
            },
            {
              "lessThan": "8dee7c278f1c2b5bb80e17a6281c3812fc8b0cdd",
              "status": "affected",
              "version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
              "versionType": "git"
            },
            {
              "lessThan": "83c2b7797742339bb768f83935f7ca33950db138",
              "status": "affected",
              "version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
              "versionType": "git"
            },
            {
              "lessThan": "30d55c8aabb261bc3f427d6b9aae7ef6206063f9",
              "status": "affected",
              "version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4layouts.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.0"
            },
            {
              "lessThan": "4.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-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: release layout stid on setlease failure\n\nnfs4_alloc_stid() publishes the new stid into cl-\u003ecl_stateids via\nidr_alloc_cyclic() under cl_lock before returning to\nnfsd4_alloc_layout_stateid(). When nfsd4_layout_setlease() then\nfails, the error path frees the layout stateid directly with\nkmem_cache_free() without ever calling idr_remove(), leaving the\nIDR slot pointing at freed slab memory. Any subsequent IDR walker\n(states_show, client teardown) dereferences the dangling pointer.\n\nThe correct teardown for an IDR-published stid is nfs4_put_stid(),\nwhich removes the IDR slot under cl_lock, dispatches sc_free\n(nfsd4_free_layout_stateid) to release ls-\u003els_file via\nnfsd4_close_layout(), and drops the nfs4_file reference in its\ntail.\n\nA second issue blocks that switch: nfsd4_free_layout_stateid()\nunconditionally inspects ls-\u003els_fence_work via\ndelayed_work_pending() under ls_lock, but\nINIT_DELAYED_WORK(\u0026ls-\u003els_fence_work, ...) currently runs only\nafter the setlease call. On the setlease-failure path the\ndestructor would touch an uninitialized delayed_work.\n\n    nfsd4_alloc_layout_stateid()\n      nfs4_alloc_stid()           /* idr_alloc_cyclic under cl_lock */\n      nfsd4_layout_setlease()     /* fails */\n        nfs4_put_stid()\n          nfsd4_free_layout_stateid()\n            delayed_work_pending(\u0026ls-\u003els_fence_work)  /* needs INIT */\n            nfsd4_close_layout()  /* nfsd_file_put(ls-\u003els_file) */\n          put_nfs4_file()\n\nFix by hoisting the ls_fenced / ls_fence_delay / INIT_DELAYED_WORK\ninitialization above the nfsd4_layout_setlease() call, and replace\nthe manual nfsd_file_put + put_nfs4_file + kmem_cache_free cleanup\nwith a single nfs4_put_stid(stp)."
    }
  ],
  "id": "CVE-2026-53399",
  "lastModified": "2026-07-20T15:16:42.533",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-19T12:16:51.063",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/30d55c8aabb261bc3f427d6b9aae7ef6206063f9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/83c2b7797742339bb768f83935f7ca33950db138"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8dee7c278f1c2b5bb80e17a6281c3812fc8b0cdd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d369e5edfaaf83a448016e2f1da392b2174be801"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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