gsd-2021-28698
Vulnerability from gsd
Modified
2023-12-13 01:23
Details
long running loops in grant table handling In order to properly monitor resource use, Xen maintains information on the grant mappings a domain may create to map grants offered by other domains. In the process of carrying out certain actions, Xen would iterate over all such entries, including ones which aren't in use anymore and some which may have been created but never used. If the number of entries for a given domain is large enough, this iterating of the entire table may tie up a CPU for too long, starving other domains or causing issues in the hypervisor itself. Note that a domain may map its own grants, i.e. there is no need for multiple domains to be involved here. A pair of "cooperating" guests may, however, cause the effects to be more severe.
Aliases
Aliases
CVE-2021-28698


To clipboard 

{
  "GSD": {
    "alias": "CVE-2021-28698",
    "description": "long running loops in grant table handling In order to properly monitor resource use, Xen maintains information on the grant mappings a domain may create to map grants offered by other domains. In the process of carrying out certain actions, Xen would iterate over all such entries, including ones which aren\u0027t in use anymore and some which may have been created but never used. If the number of entries for a given domain is large enough, this iterating of the entire table may tie up a CPU for too long, starving other domains or causing issues in the hypervisor itself. Note that a domain may map its own grants, i.e. there is no need for multiple domains to be involved here. A pair of \"cooperating\" guests may, however, cause the effects to be more severe.",
    "id": "GSD-2021-28698",
    "references": [
      "https://www.suse.com/security/cve/CVE-2021-28698.html",
      "https://www.debian.org/security/2021/dsa-4977",
      "https://linux.oracle.com/cve/CVE-2021-28698.html"
    ]
  },
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2021-28698"
      ],
      "details": "long running loops in grant table handling In order to properly monitor resource use, Xen maintains information on the grant mappings a domain may create to map grants offered by other domains. In the process of carrying out certain actions, Xen would iterate over all such entries, including ones which aren\u0027t in use anymore and some which may have been created but never used. If the number of entries for a given domain is large enough, this iterating of the entire table may tie up a CPU for too long, starving other domains or causing issues in the hypervisor itself. Note that a domain may map its own grants, i.e. there is no need for multiple domains to be involved here. A pair of \"cooperating\" guests may, however, cause the effects to be more severe.",
      "id": "GSD-2021-28698",
      "modified": "2023-12-13T01:23:29.172952Z",
      "schema_version": "1.4.0"
    }
  },
  "namespaces": {
    "cve.org": {
      "CVE_data_meta": {
        "ASSIGNER": "security@xen.org",
        "ID": "CVE-2021-28698",
        "STATE": "PUBLIC"
      },
      "affects": {
        "vendor": {
          "vendor_data": [
            {
              "product": {
                "product_data": [
                  {
                    "product_name": "xen",
                    "version": {
                      "version_data": [
                        {
                          "version_value": "4.14.x"
                        }
                      ]
                    }
                  },
                  {
                    "product_name": "xen",
                    "version": {
                      "version_data": [
                        {
                          "version_affected": "?\u003c",
                          "version_value": "4.12"
                        },
                        {
                          "version_affected": "\u003e=",
                          "version_value": "4.15.x"
                        },
                        {
                          "version_affected": "!\u003e",
                          "version_value": "xen-unstable"
                        }
                      ]
                    }
                  },
                  {
                    "product_name": "xen",
                    "version": {
                      "version_data": [
                        {
                          "version_value": "4.13.x"
                        }
                      ]
                    }
                  },
                  {
                    "product_name": "xen",
                    "version": {
                      "version_data": [
                        {
                          "version_value": "4.11.x"
                        }
                      ]
                    }
                  },
                  {
                    "product_name": "xen",
                    "version": {
                      "version_data": [
                        {
                          "version_value": "4.12.x"
                        }
                      ]
                    }
                  }
                ]
              },
              "vendor_name": "Xen"
            }
          ]
        }
      },
      "configuration": {
        "configuration_data": {
          "description": {
            "description_data": [
              {
                "lang": "eng",
                "value": "All Xen versions from at least 3.2 onwards are vulnerable in principle.\n\nSystems running with default settings are generally believed to not be\nvulnerable."
              }
            ]
          }
        }
      },
      "credit": {
        "credit_data": {
          "description": {
            "description_data": [
              {
                "lang": "eng",
                "value": "This issue was discovered by Andrew Cooper of Citrix."
              }
            ]
          }
        }
      },
      "data_format": "MITRE",
      "data_type": "CVE",
      "data_version": "4.0",
      "description": {
        "description_data": [
          {
            "lang": "eng",
            "value": "long running loops in grant table handling In order to properly monitor resource use, Xen maintains information on the grant mappings a domain may create to map grants offered by other domains. In the process of carrying out certain actions, Xen would iterate over all such entries, including ones which aren\u0027t in use anymore and some which may have been created but never used. If the number of entries for a given domain is large enough, this iterating of the entire table may tie up a CPU for too long, starving other domains or causing issues in the hypervisor itself. Note that a domain may map its own grants, i.e. there is no need for multiple domains to be involved here. A pair of \"cooperating\" guests may, however, cause the effects to be more severe."
          }
        ]
      },
      "impact": {
        "impact_data": {
          "description": {
            "description_data": [
              {
                "lang": "eng",
                "value": "Malicious or buggy guest kernels may be able to mount a Denial of\nService (DoS) attack affecting the entire system."
              }
            ]
          }
        }
      },
      "problemtype": {
        "problemtype_data": [
          {
            "description": [
              {
                "lang": "eng",
                "value": "unknown"
              }
            ]
          }
        ]
      },
      "references": {
        "reference_data": [
          {
            "name": "https://xenbits.xenproject.org/xsa/advisory-380.txt",
            "refsource": "MISC",
            "url": "https://xenbits.xenproject.org/xsa/advisory-380.txt"
          },
          {
            "name": "[oss-security] 20210901 Xen Security Advisory 380 v3 (CVE-2021-28698) - long running loops in grant table handling",
            "refsource": "MLIST",
            "url": "http://www.openwall.com/lists/oss-security/2021/09/01/2"
          },
          {
            "name": "FEDORA-2021-4f129cc0c1",
            "refsource": "FEDORA",
            "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ/"
          },
          {
            "name": "FEDORA-2021-d68ed12e46",
            "refsource": "FEDORA",
            "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FZCNPSRPGFCQRYE2BI4D4Q4SCE56ANV2/"
          },
          {
            "name": "DSA-4977",
            "refsource": "DEBIAN",
            "url": "https://www.debian.org/security/2021/dsa-4977"
          },
          {
            "name": "FEDORA-2021-081f9bf5d2",
            "refsource": "FEDORA",
            "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/"
          },
          {
            "name": "GLSA-202208-23",
            "refsource": "GENTOO",
            "url": "https://security.gentoo.org/glsa/202208-23"
          }
        ]
      },
      "workaround": {
        "workaround_data": {
          "description": {
            "description_data": [
              {
                "lang": "eng",
                "value": "The problem can be avoided by reducing the number of grant mappings Xen\nwould allow guests to establish.  For example, setting\n\"gnttab_max_maptrack_frames=256\" on the Xen command line (available\nfrom Xen 4.5 onwards) or \"max_maptrack_frames=256\" in the xl domain\nconfigurations (available from Xen 4.10 onwards) may be low enough for\nall hardware Xen is able to run on.  Note that except for driver\ndomains, guests don\u0027t normally have a need to establish grant mappings,\ni.e. they may be okay to run with \"max_maptrack_frames=0\" in their xl\ndomain configurations.\n\n- From Xen 4.14 onwards it is also possible to alter the system wide upper\nbound of the number of grant mappings Xen would allow guests to\nestablish by writing to the /params/gnttab_max_maptrack_frames\nhypervisor file system node.  Note however that changing the value this\nway will only affect guests yet to be created on the respective host."
              }
            ]
          }
        }
      }
    },
    "nvd.nist.gov": {
      "configurations": {
        "CVE_data_version": "4.0",
        "nodes": [
          {
            "children": [],
            "cpe_match": [
              {
                "cpe23Uri": "cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*",
                "cpe_name": [],
                "versionStartIncluding": "3.2.0",
                "vulnerable": true
              }
            ],
            "operator": "OR"
          },
          {
            "children": [],
            "cpe_match": [
              {
                "cpe23Uri": "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",
                "cpe_name": [],
                "vulnerable": true
              },
              {
                "cpe23Uri": "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*",
                "cpe_name": [],
                "vulnerable": true
              },
              {
                "cpe23Uri": "cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*",
                "cpe_name": [],
                "vulnerable": true
              }
            ],
            "operator": "OR"
          },
          {
            "children": [],
            "cpe_match": [
              {
                "cpe23Uri": "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*",
                "cpe_name": [],
                "vulnerable": true
              }
            ],
            "operator": "OR"
          }
        ]
      },
      "cve": {
        "CVE_data_meta": {
          "ASSIGNER": "security@xen.org",
          "ID": "CVE-2021-28698"
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "en",
              "value": "long running loops in grant table handling In order to properly monitor resource use, Xen maintains information on the grant mappings a domain may create to map grants offered by other domains. In the process of carrying out certain actions, Xen would iterate over all such entries, including ones which aren\u0027t in use anymore and some which may have been created but never used. If the number of entries for a given domain is large enough, this iterating of the entire table may tie up a CPU for too long, starving other domains or causing issues in the hypervisor itself. Note that a domain may map its own grants, i.e. there is no need for multiple domains to be involved here. A pair of \"cooperating\" guests may, however, cause the effects to be more severe."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "en",
                  "value": "CWE-835"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://xenbits.xenproject.org/xsa/advisory-380.txt",
              "refsource": "MISC",
              "tags": [
                "Vendor Advisory"
              ],
              "url": "https://xenbits.xenproject.org/xsa/advisory-380.txt"
            },
            {
              "name": "[oss-security] 20210901 Xen Security Advisory 380 v3 (CVE-2021-28698) - long running loops in grant table handling",
              "refsource": "MLIST",
              "tags": [
                "Mailing List",
                "Third Party Advisory"
              ],
              "url": "http://www.openwall.com/lists/oss-security/2021/09/01/2"
            },
            {
              "name": "FEDORA-2021-d68ed12e46",
              "refsource": "FEDORA",
              "tags": [
                "Mailing List",
                "Third Party Advisory"
              ],
              "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FZCNPSRPGFCQRYE2BI4D4Q4SCE56ANV2/"
            },
            {
              "name": "FEDORA-2021-4f129cc0c1",
              "refsource": "FEDORA",
              "tags": [
                "Mailing List",
                "Third Party Advisory"
              ],
              "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ/"
            },
            {
              "name": "DSA-4977",
              "refsource": "DEBIAN",
              "tags": [
                "Third Party Advisory"
              ],
              "url": "https://www.debian.org/security/2021/dsa-4977"
            },
            {
              "name": "FEDORA-2021-081f9bf5d2",
              "refsource": "FEDORA",
              "tags": [
                "Mailing List",
                "Third Party Advisory"
              ],
              "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/"
            },
            {
              "name": "GLSA-202208-23",
              "refsource": "GENTOO",
              "tags": [
                "Third Party Advisory"
              ],
              "url": "https://security.gentoo.org/glsa/202208-23"
            }
          ]
        }
      },
      "impact": {
        "baseMetricV2": {
          "acInsufInfo": false,
          "cvssV2": {
            "accessComplexity": "LOW",
            "accessVector": "LOCAL",
            "authentication": "NONE",
            "availabilityImpact": "COMPLETE",
            "baseScore": 4.9,
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "vectorString": "AV:L/AC:L/Au:N/C:N/I:N/A:C",
            "version": "2.0"
          },
          "exploitabilityScore": 3.9,
          "impactScore": 6.9,
          "obtainAllPrivilege": false,
          "obtainOtherPrivilege": false,
          "obtainUserPrivilege": false,
          "severity": "MEDIUM",
          "userInteractionRequired": false
        },
        "baseMetricV3": {
          "cvssV3": {
            "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
        }
      },
      "lastModifiedDate": "2022-09-28T19:56Z",
      "publishedDate": "2021-08-27T19:15Z"
    }
  }
}


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