FKIE_CVE-2026-97557

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-10-30 13:21
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid leaking refcount in cifs_queue_oplock_break() cifs_queue_oplock_break() unconditionally takes a reference on the target file before queueing cifs_oplock_break(). Only that work item decreases the reference counter again. If another oplock break arrives while that work is still queued, queue_work() will return false and not queue this second work item. As a result, we will never reach the point to drop the file reference again and are leaking this reference. This can be triggered when interacting with a slow-responding server. As a result, later unmount operations for this file system will fail with BUG: Dentry ... still in use (1) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs) kernel BUG at fs/super.c:777! Fix this by only incrementing the reference count if the work has been queued successfully. Taking it after queue_work() is safe because all three callers hold tcon->open_file_lock across the call and _cifsFileInfo_put() decrements under that same lock, so a worker that starts the handler in the window cannot drop the reference before it has been taken.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0fb92ac85db58945ad7b970ff17674001487b3a3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/13b9519b19e6e58a6cd01e63062cd1da7bd6449a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2ed2c29dd9593637cfa25ac1eb23241b20202778
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/735a3a610136ae10f381d0909dff38e5b5c5f056
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9f2e63f1b2d5fc5b5423424902c091123e220e7e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/af0193bbf1ac8c0f67f972998b0cc629d6116cf6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/de2a6bcff2659bea40c7485115b57f0ae189fc01
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dfe7b750c7e069873a8a57a11c816831a235618a
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "13b9519b19e6e58a6cd01e63062cd1da7bd6449a",
              "status": "affected",
              "version": "b98749cac4a695f084a5ff076f4510b23e353ecd",
              "versionType": "git"
            },
            {
              "lessThan": "0fb92ac85db58945ad7b970ff17674001487b3a3",
              "status": "affected",
              "version": "b98749cac4a695f084a5ff076f4510b23e353ecd",
              "versionType": "git"
            },
            {
              "lessThan": "735a3a610136ae10f381d0909dff38e5b5c5f056",
              "status": "affected",
              "version": "b98749cac4a695f084a5ff076f4510b23e353ecd",
              "versionType": "git"
            },
            {
              "lessThan": "de2a6bcff2659bea40c7485115b57f0ae189fc01",
              "status": "affected",
              "version": "b98749cac4a695f084a5ff076f4510b23e353ecd",
              "versionType": "git"
            },
            {
              "lessThan": "af0193bbf1ac8c0f67f972998b0cc629d6116cf6",
              "status": "affected",
              "version": "b98749cac4a695f084a5ff076f4510b23e353ecd",
              "versionType": "git"
            },
            {
              "lessThan": "2ed2c29dd9593637cfa25ac1eb23241b20202778",
              "status": "affected",
              "version": "b98749cac4a695f084a5ff076f4510b23e353ecd",
              "versionType": "git"
            },
            {
              "lessThan": "dfe7b750c7e069873a8a57a11c816831a235618a",
              "status": "affected",
              "version": "b98749cac4a695f084a5ff076f4510b23e353ecd",
              "versionType": "git"
            },
            {
              "lessThan": "9f2e63f1b2d5fc5b5423424902c091123e220e7e",
              "status": "affected",
              "version": "b98749cac4a695f084a5ff076f4510b23e353ecd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "2429fcf06d3cb962693868ab0a927c9038f12a2d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "53fc31a4853e30d6e8f142b824f724da27ff3e40",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8092ecc306d81186a64cda42411121f4d35aaff4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ebac4d0adf68f8962bd82fcf483936edd6ec095b",
              "versionType": "git"
            },
            {
              "lessThan": "3.17",
              "status": "affected",
              "version": "3.16.72",
              "versionType": "semver"
            },
            {
              "lessThan": "4.10",
              "status": "affected",
              "version": "4.9.171",
              "versionType": "semver"
            },
            {
              "lessThan": "4.15",
              "status": "affected",
              "version": "4.14.114",
              "versionType": "semver"
            },
            {
              "lessThan": "4.20",
              "status": "affected",
              "version": "4.19.37",
              "versionType": "semver"
            },
            {
              "lessThan": "5.1",
              "status": "affected",
              "version": "5.0.10",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.1"
            },
            {
              "lessThan": "5.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.273",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "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\nsmb: client: avoid leaking refcount in cifs_queue_oplock_break()\n\ncifs_queue_oplock_break() unconditionally takes a reference on the\ntarget file before queueing cifs_oplock_break(). Only that work item\ndecreases the reference counter again.\n\nIf another oplock break arrives while that work is still queued,\nqueue_work() will return false and not queue this second work item. As a\nresult, we will never reach the point to drop the file reference again\nand are leaking this reference. This can be triggered when interacting\nwith a slow-responding server.\n\nAs a result, later unmount operations for this file system will fail with\n\n  BUG: Dentry ... still in use (1) [unmount of cifs cifs]\n  VFS: Busy inodes after unmount of cifs (cifs)\n  kernel BUG at fs/super.c:777!\n\nFix this by only incrementing the reference count if the work has been\nqueued successfully. Taking it after queue_work() is safe because all\nthree callers hold tcon-\u003eopen_file_lock across the call and\n_cifsFileInfo_put() decrements under that same lock, so a worker that\nstarts the handler in the window cannot drop the reference before it has\nbeen taken."
    }
  ],
  "id": "CVE-2026-97557",
  "lastModified": "2026-10-30T13:21:07.803",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-25T11:17:06.193",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0fb92ac85db58945ad7b970ff17674001487b3a3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/13b9519b19e6e58a6cd01e63062cd1da7bd6449a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2ed2c29dd9593637cfa25ac1eb23241b20202778"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/735a3a610136ae10f381d0909dff38e5b5c5f056"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9f2e63f1b2d5fc5b5423424902c091123e220e7e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/af0193bbf1ac8c0f67f972998b0cc629d6116cf6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/de2a6bcff2659bea40c7485115b57f0ae189fc01"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dfe7b750c7e069873a8a57a11c816831a235618a"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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