CVE-2026-89681

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix layout fence worker double-reference race The workqueue core clears WORK_STRUCT_PENDING before the callback is invoked, so delayed_work_pending() in lm_breaker_timedout() can return false while the fence worker is already running. This lets the breaker take a duplicate sc_count reference and schedule a new worker that coalesces with the in-progress one. The extra reference is never put, leaking the layout stateid. Replace the racy delayed_work_pending() check with an ls_fence_inflight boolean set atomically with refcount_inc_not_zero() under ls_lock, and cleared under ls_lock before the final nfs4_put_stid() on the dispose path; the retry path intentionally retains it. Remove the self-rearm mod_delayed_work() at the top of the worker.

Severity

CRITICAL

CVSS score

9.8 (v3.1)

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-11 20:19:54.917000

Last modified

2026-10-19 09:18:06.443000

View original CVE JSON

{
  "id": "CVE-2026-89681",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-11T20:19:54.917",
  "lastModified": "2026-10-19T09:18:06.443",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix layout fence worker double-reference race\n\nThe workqueue core clears WORK_STRUCT_PENDING before the callback\nis invoked, so delayed_work_pending() in lm_breaker_timedout() can\nreturn false while the fence worker is already running. This lets\nthe breaker take a duplicate sc_count reference and schedule a new\nworker that coalesces with the in-progress one. The extra reference\nis never put, leaking the layout stateid.\n\nReplace the racy delayed_work_pending() check with an\nls_fence_inflight boolean set atomically with\nrefcount_inc_not_zero() under ls_lock, and cleared under ls_lock\nbefore the final nfs4_put_stid() on the dispose path; the retry\npath intentionally retains it.  Remove the self-rearm\nmod_delayed_work() at the top of the worker."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/nfsd/nfs4layouts.c",
            "fs/nfsd/state.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "f52792f484ba2316853736856dde19b7e7458861",
              "lessThan": "a278d361e0e8f242211891193d56483a7a9f47a8",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f52792f484ba2316853736856dde19b7e7458861",
              "lessThan": "8580571227451384399b3fa53fcde19848c48e5a",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/nfsd/nfs4layouts.c",
            "fs/nfsd/state.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "7.1",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "7.1",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.4",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "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:H/I:H/A:H",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/8580571227451384399b3fa53fcde19848c48e5a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a278d361e0e8f242211891193d56483a7a9f47a8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}