FKIE_CVE-2021-26931

Vulnerability from fkie_nvd - Published: 2021-02-17 02:15 - Updated: 2026-06-17 03:44
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
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.
References
cve@mitre.orghttp://xenbits.xen.org/xsa/advisory-362.htmlPatch, Third Party Advisory
cve@mitre.orghttps://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=3194a1746e8aabe86075fd3c5e7cf1f4632d7f16
cve@mitre.orghttps://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=5a264285ed1cd32e26d9de4f3c8c6855e467fd63
cve@mitre.orghttps://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7c77474b2d22176d2bfb592ec74e0f2cb71352c9
cve@mitre.orghttps://lists.debian.org/debian-lts-announce/2021/03/msg00010.htmlMailing List, Third Party Advisory
cve@mitre.orghttps://lists.debian.org/debian-lts-announce/2021/03/msg00035.htmlMailing List, Third Party Advisory
cve@mitre.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2XQR52ICKRK3GC4HDWLMWF2U55YGAR63/
cve@mitre.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GWQWPWYZRXVFJI5M3VCM72X27IB7CKOB/
cve@mitre.orghttps://security.netapp.com/advisory/ntap-20210326-0001/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108http://xenbits.xen.org/xsa/advisory-362.htmlPatch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=3194a1746e8aabe86075fd3c5e7cf1f4632d7f16
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=5a264285ed1cd32e26d9de4f3c8c6855e467fd63
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7c77474b2d22176d2bfb592ec74e0f2cb71352c9
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2021/03/msg00010.htmlMailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2021/03/msg00035.htmlMailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2XQR52ICKRK3GC4HDWLMWF2U55YGAR63/
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GWQWPWYZRXVFJI5M3VCM72X27IB7CKOB/
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20210326-0001/Third Party Advisory
Impacted products
Vendor Product Version
linux linux_kernel *
fedoraproject fedora 32
fedoraproject fedora 33
debian debian_linux 9.0
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "60442DCE-D80D-4512-BAE8-E1C5E54BBBF2",
              "versionEndIncluding": "5.10.16",
              "versionStartIncluding": "2.6.39",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
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              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",
              "matchCriteriaId": "E460AA51-FCDA-46B9-AE97-E6676AA5E194",
              "vulnerable": true
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              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "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\u0027t 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 detect\u00f3 un problema en el kernel de Linux versiones 2.6.39 hasta 5.10.16, como es usado en Xen.\u0026#xa0;Los backends de bloque, red y SCSI consideran determinados errores como un bug simple, causando deliberadamente un bloqueo del kernel.\u0026#xa0;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.\u0026#xa0;Sin embargo, las asignaciones de memoria que pueden causar tales bloqueos ocurren solo cuando Linux se ejecuta en modo PV.\u0026#xa0;Esto afecta a los archivos drivers/block/xen-blkback/blkback.c y drivers/xen/xen-scsiback.c"
    }
  ],
  "id": "CVE-2021-26931",
  "lastModified": "2026-06-17T03:44:01.953",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "LOW",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "LOCAL",
          "authentication": "NONE",
          "availabilityImpact": "PARTIAL",
          "baseScore": 1.9,
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "vectorString": "AV:L/AC:M/Au:N/C:N/I:N/A:P",
          "version": "2.0"
        },
        "exploitabilityScore": 3.4,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "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"
      }
    ]
  },
  "published": "2021-02-17T02:15:12.987",
  "references": [
    {
      "source": "cve@mitre.org",
      "tags": [
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        "Third Party Advisory"
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      "url": "http://xenbits.xen.org/xsa/advisory-362.html"
    },
    {
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    {
      "source": "cve@mitre.org",
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    },
    {
      "source": "cve@mitre.org",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2XQR52ICKRK3GC4HDWLMWF2U55YGAR63/"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GWQWPWYZRXVFJI5M3VCM72X27IB7CKOB/"
    },
    {
      "source": "cve@mitre.org",
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  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

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