{
  "document": {
    "acknowledgments": [
      {
        "names": [
          "Microsoft Platform Security \u0026 Vulnerability Research"
        ]
      }
    ],
    "aggregate_severity": {
      "namespace": "https://www.microsoft.com/en-us/msrc/security-update-severity-rating-system",
      "text": "Important"
    },
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      },
      {
        "category": "general",
        "text": "Required. The vulnerability documented by this CVE requires customer action to resolve.",
        "title": "Customer Action"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2021-26877 Windows DNS Server Remote Code Execution Vulnerability - HTML",
        "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26877"
      },
      {
        "category": "self",
        "summary": "CVE-2021-26877 Windows DNS Server Remote Code Execution Vulnerability - CSAF",
        "url": "https://msrc.microsoft.com/csaf/advisories/2021/msrc_cve-2021-26877.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Exploitability Index",
        "url": "https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "Windows DNS Server Remote Code Execution Vulnerability",
    "tracking": {
      "current_release_date": "2021-03-09T08:00:00.000Z",
      "generator": {
        "date": "2026-08-19T16:30:03.175Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2021-26877",
      "initial_release_date": "2021-03-09T08:00:00.000Z",
      "revision_history": [
        {
          "date": "2021-03-09T08:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c10.0.19043.867",
            "product": {
              "name": "Windows Server, version 20H2 (Server Core Installation) \u003c10.0.19043.867",
              "product_id": "1"
            }
          },
          {
            "category": "product_version",
            "name": "10.0.19043.867",
            "product": {
              "name": "Windows Server, version 20H2 (Server Core Installation) 10.0.19043.867",
              "product_id": "11803"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server, version 20H2 (Server Core Installation)"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c10.0.17763.1817",
            "product": {
              "name": "Windows Server 2019 \u003c10.0.17763.1817",
              "product_id": "5"
            }
          },
          {
            "category": "product_version",
            "name": "10.0.17763.1817",
            "product": {
              "name": "Windows Server 2019 10.0.17763.1817",
              "product_id": "11571"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2019"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c10.0.17763.1817",
            "product": {
              "name": "Windows Server 2019 (Server Core installation) \u003c10.0.17763.1817",
              "product_id": "4"
            }
          },
          {
            "category": "product_version",
            "name": "10.0.17763.1817",
            "product": {
              "name": "Windows Server 2019 (Server Core installation) 10.0.17763.1817",
              "product_id": "11572"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2019 (Server Core installation)"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c10.0.18363.1440",
            "product": {
              "name": "Windows Server, version 1909 (Server Core installation) \u003c10.0.18363.1440",
              "product_id": "3"
            }
          },
          {
            "category": "product_version",
            "name": "10.0.18363.1440",
            "product": {
              "name": "Windows Server, version 1909 (Server Core installation) 10.0.18363.1440",
              "product_id": "11715"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server, version 1909 (Server Core installation)"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c10.0.19043.867",
            "product": {
              "name": "Windows Server, version 2004 (Server Core installation) \u003c10.0.19043.867",
              "product_id": "2"
            }
          },
          {
            "category": "product_version",
            "name": "10.0.19043.867",
            "product": {
              "name": "Windows Server, version 2004 (Server Core installation) 10.0.19043.867",
              "product_id": "11769"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server, version 2004 (Server Core installation)"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c10.0.14393.4283",
            "product": {
              "name": "Windows Server 2016 \u003c10.0.14393.4283",
              "product_id": "7"
            }
          },
          {
            "category": "product_version",
            "name": "10.0.14393.4283",
            "product": {
              "name": "Windows Server 2016 10.0.14393.4283",
              "product_id": "10816"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2016"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c10.0.14393.4283",
            "product": {
              "name": "Windows Server 2016 (Server Core installation) \u003c10.0.14393.4283",
              "product_id": "6"
            }
          },
          {
            "category": "product_version",
            "name": "10.0.14393.4283",
            "product": {
              "name": "Windows Server 2016 (Server Core installation) 10.0.14393.4283",
              "product_id": "10855"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2016 (Server Core installation)"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.0.6003.21070",
            "product": {
              "name": "Windows Server 2008 for 32-bit Systems Service Pack 2 \u003c6.0.6003.21070",
              "product_id": "17"
            }
          },
          {
            "category": "product_version",
            "name": "6.0.6003.21070",
            "product": {
              "name": "Windows Server 2008 for 32-bit Systems Service Pack 2 6.0.6003.21070",
              "product_id": "9312"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2008 for 32-bit Systems Service Pack 2"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.0.6003.21070",
            "product": {
              "name": "Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) \u003c6.0.6003.21070",
              "product_id": "12"
            }
          },
          {
            "category": "product_version",
            "name": "6.0.6003.21070",
            "product": {
              "name": "Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 6.0.6003.21070",
              "product_id": "10287"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.0.6003.21070",
            "product": {
              "name": "Windows Server 2008 for x64-based Systems Service Pack 2 \u003c6.0.6003.21070",
              "product_id": "16"
            }
          },
          {
            "category": "product_version",
            "name": "6.0.6003.21070",
            "product": {
              "name": "Windows Server 2008 for x64-based Systems Service Pack 2 6.0.6003.21070",
              "product_id": "9318"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2008 for x64-based Systems Service Pack 2"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.0.6003.21070",
            "product": {
              "name": "Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) \u003c6.0.6003.21070",
              "product_id": "15"
            }
          },
          {
            "category": "product_version",
            "name": "6.0.6003.21070",
            "product": {
              "name": "Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 6.0.6003.21070",
              "product_id": "9344"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.1.7601.24566",
            "product": {
              "name": "Windows Server 2008 R2 for x64-based Systems Service Pack 1 \u003c6.1.7601.24566",
              "product_id": "13"
            }
          },
          {
            "category": "product_version",
            "name": "6.1.7601.24566",
            "product": {
              "name": "Windows Server 2008 R2 for x64-based Systems Service Pack 1 6.1.7601.24566",
              "product_id": "10051"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2008 R2 for x64-based Systems Service Pack 1"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.1.7601.24566",
            "product": {
              "name": "Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) \u003c6.1.7601.24566",
              "product_id": "14"
            }
          },
          {
            "category": "product_version",
            "name": "6.1.7601.24566",
            "product": {
              "name": "Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 6.1.7601.24566",
              "product_id": "10049"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.2.9200.23298",
            "product": {
              "name": "Windows Server 2012 \u003c6.2.9200.23298",
              "product_id": "11"
            }
          },
          {
            "category": "product_version",
            "name": "6.2.9200.23298",
            "product": {
              "name": "Windows Server 2012 6.2.9200.23298",
              "product_id": "10378"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2012"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.2.9200.23298",
            "product": {
              "name": "Windows Server 2012 (Server Core installation) \u003c6.2.9200.23298",
              "product_id": "10"
            }
          },
          {
            "category": "product_version",
            "name": "6.2.9200.23298",
            "product": {
              "name": "Windows Server 2012 (Server Core installation) 6.2.9200.23298",
              "product_id": "10379"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2012 (Server Core installation)"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.3.9600.19968",
            "product": {
              "name": "Windows Server 2012 R2 \u003c6.3.9600.19968",
              "product_id": "9"
            }
          },
          {
            "category": "product_version",
            "name": "6.3.9600.19968",
            "product": {
              "name": "Windows Server 2012 R2 6.3.9600.19968",
              "product_id": "10483"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2012 R2"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c6.3.9600.19968",
            "product": {
              "name": "Windows Server 2012 R2 (Server Core installation) \u003c6.3.9600.19968",
              "product_id": "8"
            }
          },
          {
            "category": "product_version",
            "name": "6.3.9600.19968",
            "product": {
              "name": "Windows Server 2012 R2 (Server Core installation) 6.3.9600.19968",
              "product_id": "10543"
            }
          }
        ],
        "category": "product_name",
        "name": "Windows Server 2012 R2 (Server Core installation)"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2021-26877",
      "notes": [
        {
          "category": "general",
          "text": "Microsoft",
          "title": "Assigning CNA"
        },
        {
          "category": "faq",
          "text": "No, this vulnerability is only exploitable if the server is configured to be a DNS server.",
          "title": "If my server is not configured to be a DNS server, it is vulnerable?"
        },
        {
          "category": "faq",
          "text": "Enabling Secure Zone Updates constrains the potential sources of the attack, but does not completely prevent it. For example, a malicious insider could attack a \u201csecure zone update\u201d DNS server from a domain-joined computer. This is only a partial mitigation.\nThis vulnerability impacts any DNS server. The surrounding configuration can limit possible vectors/sources for the attack, but proper mitigation requires this month\u2019s security update patch.",
          "title": "Can this vulnerability by mitigated by enabling Secure Zone Updates?"
        }
      ],
      "product_status": {
        "fixed": [
          "9312",
          "9318",
          "9344",
          "10049",
          "10051",
          "10287",
          "10378",
          "10379",
          "10483",
          "10543",
          "10816",
          "10855",
          "11571",
          "11572",
          "11715",
          "11769",
          "11803"
        ],
        "known_affected": [
          "1",
          "2",
          "3",
          "4",
          "5",
          "6",
          "7",
          "8",
          "9",
          "10",
          "11",
          "12",
          "13",
          "14",
          "15",
          "16",
          "17"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2021-26877 Windows DNS Server Remote Code Execution Vulnerability - HTML",
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26877"
        },
        {
          "category": "self",
          "summary": "CVE-2021-26877 Windows DNS Server Remote Code Execution Vulnerability - CSAF",
          "url": "https://msrc.microsoft.com/csaf/advisories/2021/msrc_cve-2021-26877.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "10.0.19043.867:Security Update:https://support.microsoft.com/help/5000802",
          "product_ids": [
            "1",
            "2"
          ],
          "url": "https://support.microsoft.com/help/5000802"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "10.0.17763.1817:Security Update:https://support.microsoft.com/help/5000822",
          "product_ids": [
            "5",
            "4"
          ],
          "url": "https://support.microsoft.com/help/5000822"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "10.0.18363.1440:Security Update:https://support.microsoft.com/help/5000808",
          "product_ids": [
            "3"
          ],
          "url": "https://support.microsoft.com/help/5000808"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "10.0.14393.4283:Security Update:https://support.microsoft.com/help/5000803",
          "product_ids": [
            "7",
            "6"
          ],
          "url": "https://support.microsoft.com/help/5000803"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "6.0.6003.21070:Monthly Rollup:https://support.microsoft.com/help/5000844",
          "product_ids": [
            "17",
            "12",
            "16",
            "15"
          ],
          "url": "https://support.microsoft.com/help/5000844"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "Security Only:https://support.microsoft.com/help/5000856",
          "product_ids": [
            "17",
            "12",
            "16",
            "15"
          ],
          "url": "https://support.microsoft.com/help/5000856"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "6.1.7601.24566:Monthly Rollup:https://support.microsoft.com/help/5000841",
          "product_ids": [
            "13",
            "14"
          ],
          "url": "https://support.microsoft.com/help/5000841"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "Security Only:https://support.microsoft.com/help/5000851",
          "product_ids": [
            "13",
            "14"
          ],
          "url": "https://support.microsoft.com/help/5000851"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "6.2.9200.23298:Monthly Rollup:https://support.microsoft.com/help/5000847",
          "product_ids": [
            "11",
            "10"
          ],
          "url": "https://support.microsoft.com/help/5000847"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "Security Only:https://support.microsoft.com/help/5000840",
          "product_ids": [
            "11",
            "10"
          ],
          "url": "https://support.microsoft.com/help/5000840"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "6.3.9600.19968:Monthly Rollup:https://support.microsoft.com/help/5000848",
          "product_ids": [
            "9",
            "8"
          ],
          "url": "https://support.microsoft.com/help/5000848"
        },
        {
          "category": "vendor_fix",
          "date": "2021-03-09T08:00:00.000Z",
          "details": "Security Only:https://support.microsoft.com/help/5000853",
          "product_ids": [
            "9",
            "8"
          ],
          "url": "https://support.microsoft.com/help/5000853"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "environmentalScore": 0.0,
            "exploitCodeMaturity": "UNPROVEN",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "UNCHANGED",
            "temporalScore": 8.5,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "1",
            "2",
            "3",
            "4",
            "5",
            "6",
            "7",
            "8",
            "9",
            "10",
            "11",
            "12",
            "13",
            "14",
            "15",
            "16",
            "17"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Remote Code Execution"
        },
        {
          "category": "exploit_status",
          "details": "Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation More Likely;Older Software Release:Exploitation More Likely"
        }
      ],
      "title": "Windows DNS Server Remote Code Execution Vulnerability"
    }
  ]
}