FKIE_CVE-2021-28701

Vulnerability from fkie_nvd - Published: 2021-09-08 14:15 - Updated: 2026-06-17 03:46
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
Another race in XENMAPSPACE_grant_table handling Guests are permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, are de-allocated when a guest switches (back) from v2 to v1. Freeing such pages requires that the hypervisor enforce that no parallel request can result in the addition of a mapping of such a page to a guest. That enforcement was missing, allowing guests to retain access to pages that were freed and perhaps re-used for other purposes. Unfortunately, when XSA-379 was being prepared, this similar issue was not noticed.
References
security@xen.orghttp://www.openwall.com/lists/oss-security/2021/09/08/2Mailing List, Third Party Advisory
security@xen.orghttp://xenbits.xen.org/xsa/advisory-384.htmlVendor Advisory
security@xen.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3HEHUIUWSSMCQGQY3GWX4J2SZGYP5W2Z/
security@xen.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEHZLIR5DFYYQBH55AERWHLO54OFU42C/
security@xen.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L4MI3MQAPGILCLXBGQWPZHGE3ALSO4ZU/
security@xen.orghttps://security.gentoo.org/glsa/202208-23Third Party Advisory
security@xen.orghttps://www.debian.org/security/2021/dsa-4977Third Party Advisory
security@xen.orghttps://xenbits.xenproject.org/xsa/advisory-384.txtVendor Advisory
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2021/09/08/2Mailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108http://xenbits.xen.org/xsa/advisory-384.htmlVendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3HEHUIUWSSMCQGQY3GWX4J2SZGYP5W2Z/
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEHZLIR5DFYYQBH55AERWHLO54OFU42C/
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L4MI3MQAPGILCLXBGQWPZHGE3ALSO4ZU/
af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202208-23Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.debian.org/security/2021/dsa-4977Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://xenbits.xenproject.org/xsa/advisory-384.txtVendor Advisory
Impacted products
Vendor Product Version
xen xen *
debian debian_linux 11.0
fedoraproject fedora 33
fedoraproject fedora 34
fedoraproject fedora 35
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "xen",
          "vendor": "Xen",
          "versions": [
            {
              "lessThan": "4.12",
              "status": "unknown",
              "version": "unspecified",
              "versionType": "custom"
            },
            {
              "lessThan": "unspecified",
              "status": "affected",
              "version": "4.15.x",
              "versionType": "custom"
            },
            {
              "lessThan": "unspecified",
              "status": "unaffected",
              "version": "next of xen-unstable",
              "versionType": "custom"
            }
          ]
        },
        {
          "product": "xen",
          "vendor": "Xen",
          "versions": [
            {
              "status": "affected",
              "version": "4.11.x"
            }
          ]
        },
        {
          "product": "xen",
          "vendor": "Xen",
          "versions": [
            {
              "lessThan": "4.12",
              "status": "unknown",
              "version": "unspecified",
              "versionType": "custom"
            },
            {
              "lessThan": "unspecified",
              "status": "affected",
              "version": "4.12.x",
              "versionType": "custom"
            },
            {
              "lessThan": "unspecified",
              "status": "unaffected",
              "version": "next of 4.14.x",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "security@xen.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "3E095C1C-0DC6-4380-9333-477B13273E9E",
              "versionStartIncluding": "4.0.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*",
              "matchCriteriaId": "FA6FEEC2-9F11-4643-8827-749718254FED",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",
              "matchCriteriaId": "E460AA51-FCDA-46B9-AE97-E6676AA5E194",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*",
              "matchCriteriaId": "A930E247-0B43-43CB-98FF-6CE7B8189835",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*",
              "matchCriteriaId": "80E516C0-98A4-4ADE-B69F-66A772E2BAAA",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Another race in XENMAPSPACE_grant_table handling Guests are permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, are de-allocated when a guest switches (back) from v2 to v1. Freeing such pages requires that the hypervisor enforce that no parallel request can result in the addition of a mapping of such a page to a guest. That enforcement was missing, allowing guests to retain access to pages that were freed and perhaps re-used for other purposes. Unfortunately, when XSA-379 was being prepared, this similar issue was not noticed."
    },
    {
      "lang": "es",
      "value": "Otra carrera en el manejo de la funci\u00f3n XENMAPSPACE_grant_table de los Hu\u00e9spedes, se les permite el acceso a determinadas p\u00e1ginas de memoria propiedad de Xen. La mayor\u00eda de estas p\u00e1ginas permanecen asignadas / asociadas a un hu\u00e9sped durante toda su vida. Las p\u00e1ginas de estado de la tabla Grant v2, sin embargo, se desasignan cuando un hu\u00e9sped cambia (de nuevo) de v2 a v1. Una liberaci\u00f3n de dichas p\u00e1ginas requiere que el hipervisor haga cumplir que ninguna petici\u00f3n paralela pueda resultar en la adici\u00f3n de un mapeo de dicha p\u00e1gina a un hu\u00e9sped. Esta aplicaci\u00f3n no exist\u00eda, permitiendo a los hu\u00e9spedes mantener el acceso a las p\u00e1ginas liberadas y quiz\u00e1s reusarlas para otros fines. Desafortunadamente, cuando fue preparada la XSA-379, no se advirti\u00f3 este problema similar"
    }
  ],
  "id": "CVE-2021-28701",
  "lastModified": "2026-06-17T03:46:49.863",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "MEDIUM",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "LOCAL",
          "authentication": "NONE",
          "availabilityImpact": "PARTIAL",
          "baseScore": 4.4,
          "confidentialityImpact": "PARTIAL",
          "integrityImpact": "PARTIAL",
          "vectorString": "AV:L/AC:M/Au:N/C:P/I:P/A:P",
          "version": "2.0"
        },
        "exploitabilityScore": 3.4,
        "impactScore": 6.4,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.1,
        "impactScore": 6.0,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2021-09-08T14:15:08.547",
  "references": [
    {
      "source": "security@xen.org",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "http://www.openwall.com/lists/oss-security/2021/09/08/2"
    },
    {
      "source": "security@xen.org",
      "tags": [
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      "url": "http://xenbits.xen.org/xsa/advisory-384.html"
    },
    {
      "source": "security@xen.org",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3HEHUIUWSSMCQGQY3GWX4J2SZGYP5W2Z/"
    },
    {
      "source": "security@xen.org",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEHZLIR5DFYYQBH55AERWHLO54OFU42C/"
    },
    {
      "source": "security@xen.org",
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    },
    {
      "source": "security@xen.org",
      "tags": [
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      "url": "https://security.gentoo.org/glsa/202208-23"
    },
    {
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      "tags": [
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      ],
      "url": "https://www.debian.org/security/2021/dsa-4977"
    },
    {
      "source": "security@xen.org",
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      "url": "https://xenbits.xenproject.org/xsa/advisory-384.txt"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
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    },
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    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3HEHUIUWSSMCQGQY3GWX4J2SZGYP5W2Z/"
    },
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    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L4MI3MQAPGILCLXBGQWPZHGE3ALSO4ZU/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
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      ],
      "url": "https://xenbits.xenproject.org/xsa/advisory-384.txt"
    }
  ],
  "sourceIdentifier": "security@xen.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-362"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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