FKIE_CVE-2021-47491

Vulnerability from fkie_nvd - Published: 2024-05-22 09:15 - Updated: 2025-09-29 16:37
Severity ?
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: mm: khugepaged: skip huge page collapse for special files The read-only THP for filesystems will collapse THP for files opened readonly and mapped with VM_EXEC. The intended usecase is to avoid TLB misses for large text segments. But it doesn't restrict the file types so a THP could be collapsed for a non-regular file, for example, block device, if it is opened readonly and mapped with EXEC permission. This may cause bugs, like [1] and [2]. This is definitely not the intended usecase, so just collapse THP for regular files in order to close the attack surface. [shy828301@gmail.com: fix vm_file check [3]]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5fcb6fce74ffa614d964667110cf1a516c48c6d9Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6d67b2a73b8e3a079c355bab3c1aef7d85a044b8Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a4aeaa06d45e90f9b279f0b09de84bd00006e733Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/5fcb6fce74ffa614d964667110cf1a516c48c6d9Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/6d67b2a73b8e3a079c355bab3c1aef7d85a044b8Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/a4aeaa06d45e90f9b279f0b09de84bd00006e733Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 5.15
linux linux_kernel 5.15
linux linux_kernel 5.15
linux linux_kernel 5.15
linux linux_kernel 5.15
linux linux_kernel 5.15
linux linux_kernel 5.15
To clipboard 

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: khugepaged: skip huge page collapse for special files\n\nThe read-only THP for filesystems will collapse THP for files opened\nreadonly and mapped with VM_EXEC.  The intended usecase is to avoid TLB\nmisses for large text segments.  But it doesn\u0027t restrict the file types\nso a THP could be collapsed for a non-regular file, for example, block\ndevice, if it is opened readonly and mapped with EXEC permission.  This\nmay cause bugs, like [1] and [2].\n\nThis is definitely not the intended usecase, so just collapse THP for\nregular files in order to close the attack surface.\n\n[shy828301@gmail.com: fix vm_file check [3]]"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mm: khugepaged: omitir el colapso de p\u00e1gina enorme para archivos especiales El THP de solo lectura para sistemas de archivos colapsar\u00e1 el THP para archivos abiertos de solo lectura y asignados con VM_EXEC. El caso de uso previsto es evitar errores de TLB en segmentos de texto grandes. Pero no restringe los tipos de archivos, por lo que un THP podr\u00eda contraerse para un archivo no normal, por ejemplo, un dispositivo de bloqueo, si se abre en modo de solo lectura y se asigna con permiso EXEC. Esto puede causar errores, como [1] y [2]. Definitivamente este no es el caso de uso previsto, as\u00ed que simplemente contraiga THP para archivos normales para cerrar la superficie de ataque. [shy828301@gmail.com: corrige la verificaci\u00f3n de vm_file [3]]"
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  "id": "CVE-2021-47491",
  "lastModified": "2025-09-29T16:37:28.290",
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          "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"
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        "impactScore": 3.6,
        "source": "nvd@nist.gov",
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  "published": "2024-05-22T09:15:10.917",
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