FKIE_CVE-2019-15794

Vulnerability from fkie_nvd - Published: 2020-04-24 00:15 - Updated: 2026-06-17 02:21
Severity
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
6.7 (Medium) - CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Summary
Overlayfs in the Linux kernel and shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, both replace vma->vm_file in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vm_file points. On upstream kernels this is not an issue, as no callers dereference vm_file following after call_mmap() returns an error. However, the aufs patchs change mmap_region() to replace the fput() using a local variable with vma_fput(), which will fput() vm_file, leading to a refcount underflow.
References
security@ubuntu.comhttps://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=270d16ae48a4dbf1c7e25e94cc3e38b4bea37635Mailing List, Patch, Third Party Advisory
security@ubuntu.comhttps://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=ef81780548d20a786cc77ed4203fca146fd81ce3Mailing List, Patch, Third Party Advisory
security@ubuntu.comhttps://usn.ubuntu.com/usn/usn-4208-1Third Party Advisory
security@ubuntu.comhttps://usn.ubuntu.com/usn/usn-4209-1Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=270d16ae48a4dbf1c7e25e94cc3e38b4bea37635Mailing List, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=ef81780548d20a786cc77ed4203fca146fd81ce3Mailing List, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/usn/usn-4208-1Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/usn/usn-4209-1Third Party Advisory
Impacted products
Vendor Product Version
linux linux_kernel 5.0
linux linux_kernel 5.3
canonical ubuntu_linux 18.04
canonical ubuntu_linux 19.10
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "Linux kernel",
          "vendor": "Ubuntu",
          "versions": [
            {
              "lessThan": "5.3.0-24.26",
              "status": "affected",
              "version": "5.3 kernel",
              "versionType": "custom"
            },
            {
              "lessThan": "5.0.0-37.40",
              "status": "affected",
              "version": "5.0 kernel",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "security@ubuntu.com"
    }
  ],
  "configurations": [
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              "vulnerable": true
            },
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Overlayfs in the Linux kernel and shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, both replace vma-\u003evm_file in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vm_file points. On upstream kernels this is not an issue, as no callers dereference vm_file following after call_mmap() returns an error. However, the aufs patchs change mmap_region() to replace the fput() using a local variable with vma_fput(), which will fput() vm_file, leading to a refcount underflow."
    },
    {
      "lang": "es",
      "value": "Overlayfs en el kernel de Linux y shiftfs, un parche no upstream para el kernel de Linux incluido en las series de kernel Ubuntu versiones 5.0 y 5.3, ambos reemplazan vma-\u0026gt;vm_file en sus manejadores de mmap. En el error el valor original no se restaura, y se pone la referencia para el archivo al que apunta vm_file. En los n\u00facleos ascendentes esto no es un problema, ya que ninguna de las llamadas que siguen a vm_file despu\u00e9s de call_mmap() devuelve un error. Sin embargo, los parches de aufs cambian mmap_region() para reemplazar el fput() usando una variable local con vma_fput(), la cual fput() vm_file, lo que lleva a un subflujo de recuento."
    }
  ],
  "id": "CVE-2019-15794",
  "lastModified": "2026-06-17T02:21:05.330",
  "metrics": {
    "cvssMetricV2": [
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        "acInsufInfo": false,
        "baseSeverity": "HIGH",
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          "accessVector": "LOCAL",
          "authentication": "NONE",
          "availabilityImpact": "COMPLETE",
          "baseScore": 7.2,
          "confidentialityImpact": "COMPLETE",
          "integrityImpact": "COMPLETE",
          "vectorString": "AV:L/AC:L/Au:N/C:C/I:C/A:C",
          "version": "2.0"
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        "exploitabilityScore": 3.9,
        "impactScore": 10.0,
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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
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          "confidentialityImpact": "HIGH",
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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
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        "impactScore": 5.9,
        "source": "nvd@nist.gov",
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  "published": "2020-04-24T00:15:11.933",
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  "sourceIdentifier": "security@ubuntu.com",
  "vulnStatus": "Modified",
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      ],
      "source": "nvd@nist.gov",
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    }
  ]
}



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