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CVE-2021-26931

Estado: ModificadaMedia (5.5)—

Se detectó un problema en el kernel de Linux versiones 2.6.39 hasta 5.10.16, como es usado en Xen. Los backends de bloque, red y SCSI consideran determinados errores como un bug simple, causando deliberadamente un bloqueo del kernel. Para los errores que pueden estar al menos bajo la influencia de los invitados (como las condiciones de falta de memoria), no es correcto suponer un bug simple. Sin embargo, las asignaciones de memoria que pueden causar tales bloqueos ocurren solo cuando Linux se ejecuta en modo PV. Esto afecta a los archivos drivers/block/xen-blkback/blkback.c y drivers/xen/xen-scsiback.c

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (3)

Debian — Debian LinuxFedoraproject — FedoraLinux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2021-26931",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 1.9,
          "accessVector": "LOCAL",
          "vectorString": "AV:L/AC:M/Au:N/C:N/I:N/A:P",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "LOW",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 3.4,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
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    "cvssMetricV31": [
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        "source": "nvd@nist.gov",
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          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
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      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
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              "status": "affected",
              "version": "n/a"
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  "published": "2021-02-17T02:15:12.987",
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GWQWPWYZRXVFJI5M3VCM72X27IB7CKOB/",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  "vulnStatus": "Modified",
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      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue was discovered in the Linux kernel 2.6.39 through 5.10.16, as used in Xen. Block, net, and SCSI backends consider certain errors a plain bug, deliberately causing a kernel crash. For errors potentially being at least under the influence of guests (such as out of memory conditions), it isn't correct to assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running in PV mode, though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c."
    },
    {
      "lang": "es",
      "value": "Se detectó un problema en el kernel de Linux versiones 2.6.39 hasta 5.10.16, como es usado en Xen. Los backends de bloque, red y SCSI consideran determinados errores como un bug simple, causando deliberadamente un bloqueo del kernel. Para los errores que pueden estar al menos bajo la influencia de los invitados (como las condiciones de falta de memoria), no es correcto suponer un bug simple. Sin embargo, las asignaciones de memoria que pueden causar tales bloqueos ocurren solo cuando Linux se ejecuta en modo PV. Esto afecta a los archivos drivers/block/xen-blkback/blkback.c y drivers/xen/xen-scsiback.c"
    }
  ],
  "lastModified": "2026-06-17T03:44:01.953",
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}