FKIE_CVE-2025-39816

Vulnerability from fkie_nvd - Published: 2025-09-16 13:15 - Updated: 2026-10-19 21:10
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengths Since the buffers are mapped from userspace, it is prudent to use READ_ONCE() to read the value into a local variable, and use that for any other actions taken. Having a stable read of the buffer length avoids worrying about it changing after checking, or being read multiple times. Similarly, the buffer may well change in between it being picked and being committed. Ensure the looping for incremental ring buffer commit stops if it hits a zero sized buffer, as no further progress can be made at that point.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/390a61d284e1ced088d43928dfcf6f86fffdd780Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/695673eb5711ee5eb1769481cf1503714716a7d1Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/91f262ea2a76a02d9e37dba6637cfe6feebb20a8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/98b6fa62c84f2e129161e976a5b9b3cb4ccd117bPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "io_uring/kbuf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "695673eb5711ee5eb1769481cf1503714716a7d1",
              "status": "affected",
              "version": "ae98dbf43d755b4e111fcd086e53939bef3e9a1a",
              "versionType": "git"
            },
            {
              "lessThan": "91f262ea2a76a02d9e37dba6637cfe6feebb20a8",
              "status": "affected",
              "version": "ae98dbf43d755b4e111fcd086e53939bef3e9a1a",
              "versionType": "git"
            },
            {
              "lessThan": "390a61d284e1ced088d43928dfcf6f86fffdd780",
              "status": "affected",
              "version": "ae98dbf43d755b4e111fcd086e53939bef3e9a1a",
              "versionType": "git"
            },
            {
              "lessThan": "98b6fa62c84f2e129161e976a5b9b3cb4ccd117b",
              "status": "affected",
              "version": "ae98dbf43d755b4e111fcd086e53939bef3e9a1a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "io_uring/kbuf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.49",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.81",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "91ABE7C0-8B2A-4A71-9635-E30621CFB875",
              "versionEndExcluding": "6.12.49",
              "versionStartIncluding": "6.12",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "EB781080-7001-4FA1-B388-517FFEFBC73E",
              "versionEndExcluding": "6.16.5",
              "versionStartIncluding": "6.13",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*",
              "matchCriteriaId": "327D22EF-390B-454C-BD31-2ED23C998A1C",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*",
              "matchCriteriaId": "C730CD9A-D969-4A8E-9522-162AAF7C0EE9",
              "vulnerable": true
            },
            {
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              "matchCriteriaId": "39982C4B-716E-4B2F-8196-FA301F47807D",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengths\n\nSince the buffers are mapped from userspace, it is prudent to use\nREAD_ONCE() to read the value into a local variable, and use that for\nany other actions taken. Having a stable read of the buffer length\navoids worrying about it changing after checking, or being read multiple\ntimes.\n\nSimilarly, the buffer may well change in between it being picked and\nbeing committed. Ensure the looping for incremental ring buffer commit\nstops if it hits a zero sized buffer, as no further progress can be made\nat that point."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nio_uring/kbuf: siempre usar READ_ONCE() para leer las longitudes de b\u00fafer proporcionadas por el anillo\n\nDado que los b\u00faferes se mapean desde el espacio de usuario, es prudente usar READ_ONCE() para leer el valor en una variable local y usarla para cualquier otra acci\u00f3n realizada. Tener una lectura estable de la longitud del b\u00fafer evita preocuparse de que cambie despu\u00e9s de la verificaci\u00f3n o de que se lea varias veces.\n\nDe manera similar, el b\u00fafer bien podr\u00eda cambiar entre el momento en que se selecciona y el momento en que se confirma. Asegurar que el bucle para la confirmaci\u00f3n incremental del b\u00fafer de anillo se detenga si encuentra un b\u00fafer de tama\u00f1o cero, ya que no se puede avanzar m\u00e1s en ese punto."
    }
  ],
  "id": "CVE-2025-39816",
  "lastModified": "2026-10-19T21:10:00.160",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-39816",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-01-14T18:15:57.258196Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2025-09-16T13:15:56.790",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/390a61d284e1ced088d43928dfcf6f86fffdd780"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/695673eb5711ee5eb1769481cf1503714716a7d1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/91f262ea2a76a02d9e37dba6637cfe6feebb20a8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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      ],
      "url": "https://git.kernel.org/stable/c/98b6fa62c84f2e129161e976a5b9b3cb4ccd117b"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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