{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-23666",
        "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
        "state": "PUBLISHED",
        "assignerShortName": "microsoft",
        "dateReserved": "2026-01-14T16:59:33.464Z",
        "datePublished": "2026-04-14T16:57:53.069Z",
        "dateUpdated": "2026-08-14T16:30:50.288Z"
    },
    "containers": {
        "cna": {
            "title": ".NET Framework Denial of Service Vulnerability",
            "datePublic": "2026-04-14T14:00:00.000Z",
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.8.0",
                                    "versionEndExcluding": "4.8.4801.0"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.8.0",
                                    "versionEndExcluding": "2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.7.0",
                                    "versionEndExcluding": "2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.7.0",
                                    "versionEndExcluding": "4.8.4801.0"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.8.1",
                                    "versionEndExcluding": "2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.5.0",
                                    "versionEndExcluding": "2.0.50727.8982 & 3.0.30729.8976"
                                }
                            ]
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "vendor": "Microsoft",
                    "product": "Microsoft .NET Framework 3.5",
                    "platforms": [
                        "Windows Server 2012",
                        "Windows Server 2012 (Server Core installation)",
                        "Windows Server 2012 R2",
                        "Windows Server 2012 R2 (Server Core installation)"
                    ],
                    "versions": [
                        {
                            "version": "3.5.0",
                            "lessThan": "2.0.50727.8982 & 3.0.30729.8976",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                },
                {
                    "vendor": "Microsoft",
                    "product": "Microsoft .NET Framework 3.5 AND 4.7.2",
                    "platforms": [
                        "Windows 10 Version 1809 for 32-bit Systems",
                        "Windows 10 Version 1809 for ARM64-based Systems",
                        "Windows 10 Version 1809 for x64-based Systems"
                    ],
                    "versions": [
                        {
                            "version": "4.7.0",
                            "lessThan": "2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                },
                {
                    "vendor": "Microsoft",
                    "product": "Microsoft .NET Framework 3.5 AND 4.8",
                    "platforms": [
                        "Windows 10 Version 1809 for 32-bit Systems",
                        "Windows 10 Version 1809 for ARM64-based Systems",
                        "Windows 10 Version 1809 for x64-based Systems",
                        "Windows 10 Version 21H2 for 32-bit Systems",
                        "Windows 10 Version 21H2 for ARM64-based Systems",
                        "Windows 10 Version 21H2 for x64-based Systems",
                        "Windows 10 Version 22H2 for 32-bit Systems",
                        "Windows 10 Version 22H2 for ARM64-based Systems",
                        "Windows 10 Version 22H2 for x64-based Systems",
                        "Windows Server 2022",
                        "Windows Server 2022 (Server Core installation)"
                    ],
                    "versions": [
                        {
                            "version": "4.8.0",
                            "lessThan": "2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                },
                {
                    "vendor": "Microsoft",
                    "product": "Microsoft .NET Framework 3.5 AND 4.8.1",
                    "platforms": [
                        "Windows 10 Version 21H2 for 32-bit Systems",
                        "Windows 10 Version 21H2 for ARM64-based Systems",
                        "Windows 10 Version 21H2 for x64-based Systems",
                        "Windows 10 Version 22H2 for 32-bit Systems",
                        "Windows 10 Version 22H2 for ARM64-based Systems",
                        "Windows 10 Version 22H2 for x64-based Systems",
                        "Windows 11 Version 22H2 for ARM64-based Systems",
                        "Windows 11 Version 22H2 for x64-based Systems",
                        "Windows 11 Version 23H2 for ARM64-based Systems",
                        "Windows 11 Version 23H2 for x64-based Systems",
                        "Windows 11 Version 24H2 for ARM64-based Systems",
                        "Windows 11 Version 24H2 for x64-based Systems",
                        "Windows 11 Version 25H2 for ARM64-based Systems",
                        "Windows 11 Version 25H2 for x64-based Systems",
                        "Windows 11 Version 26H1 for ARM64-based Systems",
                        "Windows 11 version 26H1 for x64-based Systems",
                        "Windows Server 2022",
                        "Windows Server 2022 (Server Core installation)",
                        "Windows Server 2022, 23H2 Edition (Server Core installation)",
                        "Windows Server 2025",
                        "Windows Server 2025 (Server Core installation)"
                    ],
                    "versions": [
                        {
                            "version": "4.8.1",
                            "lessThan": "2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                },
                {
                    "vendor": "Microsoft",
                    "product": "Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2",
                    "platforms": [
                        "Windows Server 2012",
                        "Windows Server 2012 (Server Core installation)",
                        "Windows Server 2012 R2",
                        "Windows Server 2012 R2 (Server Core installation)"
                    ],
                    "versions": [
                        {
                            "version": "4.7.0",
                            "lessThan": "4.8.4801.0",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                },
                {
                    "vendor": "Microsoft",
                    "product": "Microsoft .NET Framework 4.8",
                    "platforms": [
                        "Windows 10 Version 1607 for 32-bit Systems",
                        "Windows 10 Version 1607 for x64-based Systems",
                        "Windows Server 2012",
                        "Windows Server 2012 (Server Core installation)",
                        "Windows Server 2012 R2",
                        "Windows Server 2012 R2 (Server Core installation)"
                    ],
                    "versions": [
                        {
                            "version": "4.8.0",
                            "lessThan": "4.8.4801.0",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "descriptions": [
                {
                    "value": "Improper input validation in .NET Framework allows an unauthorized attacker to deny service over a network.",
                    "lang": "en-US"
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "description": "CWE-755: Improper Handling of Exceptional Conditions",
                            "lang": "en-US",
                            "type": "CWE",
                            "cweId": "CWE-755"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
                "shortName": "microsoft",
                "dateUpdated": "2026-08-14T16:30:50.288Z"
            },
            "references": [
                {
                    "name": ".NET Framework Denial of Service Vulnerability",
                    "tags": [
                        "vendor-advisory",
                        "patch"
                    ],
                    "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-23666"
                }
            ],
            "metrics": [
                {
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en-US",
                            "value": "GENERAL"
                        }
                    ],
                    "cvssV3_1": {
                        "version": "3.1",
                        "baseSeverity": "HIGH",
                        "baseScore": 7.5,
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C"
                    }
                }
            ]
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-04-15T13:40:59.739058Z",
                                "id": "CVE-2026-23666",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "yes"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-04-15T13:41:08.655Z"
                }
            },
            {
                "affected": [
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/o:redhat:enterprise_linux:10"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet10.0",
                        "product": "Red Hat Enterprise Linux 10",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/o:redhat:enterprise_linux:10"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet8.0",
                        "product": "Red Hat Enterprise Linux 10",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/o:redhat:enterprise_linux:10"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet9.0",
                        "product": "Red Hat Enterprise Linux 10",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/o:redhat:enterprise_linux:8"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet10.0",
                        "product": "Red Hat Enterprise Linux 8",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/o:redhat:enterprise_linux:8"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet8.0",
                        "product": "Red Hat Enterprise Linux 8",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/o:redhat:enterprise_linux:8"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet9.0",
                        "product": "Red Hat Enterprise Linux 8",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/o:redhat:enterprise_linux:9"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet10.0",
                        "product": "Red Hat Enterprise Linux 9",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/o:redhat:enterprise_linux:9"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet8.0",
                        "product": "Red Hat Enterprise Linux 9",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/o:redhat:enterprise_linux:9"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet9.0",
                        "product": "Red Hat Enterprise Linux 9",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/a:redhat:hummingbird:1"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet10.0",
                        "product": "Red Hat Hardened Images",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/a:redhat:hummingbird:1"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet8.0",
                        "product": "Red Hat Hardened Images",
                        "vendor": "Red Hat"
                    },
                    {
                        "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                        "cpes": [
                            "cpe:/a:redhat:hummingbird:1"
                        ],
                        "defaultStatus": "unaffected",
                        "packageName": "dotnet9.0",
                        "product": "Red Hat Hardened Images",
                        "vendor": "Red Hat"
                    }
                ],
                "datePublic": "2026-04-14T16:57:53.069Z",
                "descriptions": [
                    {
                        "lang": "en",
                        "value": "A flaw was found in .NET Framework. An unauthorized attacker can exploit a race condition, which is a concurrent execution using shared resources with improper synchronization, to deny service over a network. This vulnerability can lead to a Denial of Service (DoS) for affected systems."
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "content": {
                                "namespace": "https://access.redhat.com/security/updates/classification/",
                                "value": "Important"
                            },
                            "type": "Red Hat severity rating"
                        }
                    },
                    {
                        "cvssV3_1": {
                            "attackComplexity": "LOW",
                            "attackVector": "NETWORK",
                            "availabilityImpact": "HIGH",
                            "baseScore": 7.5,
                            "baseSeverity": "HIGH",
                            "confidentialityImpact": "NONE",
                            "integrityImpact": "NONE",
                            "privilegesRequired": "NONE",
                            "scope": "UNCHANGED",
                            "userInteraction": "NONE",
                            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                            "version": "3.1"
                        },
                        "format": "CVSS"
                    }
                ],
                "problemTypes": [
                    {
                        "descriptions": [
                            {
                                "cweId": "CWE-366",
                                "description": "Race Condition within a Thread",
                                "lang": "en",
                                "type": "CWE"
                            }
                        ]
                    }
                ],
                "references": [
                    {
                        "tags": [
                            "vdb-entry",
                            "x_refsource_REDHAT"
                        ],
                        "url": "https://access.redhat.com/security/cve/CVE-2026-23666"
                    },
                    {
                        "name": "RHBZ#2458271",
                        "tags": [
                            "issue-tracking",
                            "x_refsource_REDHAT"
                        ],
                        "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2458271"
                    },
                    {
                        "tags": [
                            "x_sadp-csaf-vex"
                        ],
                        "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23666.json"
                    }
                ],
                "timeline": [
                    {
                        "lang": "en",
                        "time": "2026-04-14T18:01:54.434Z",
                        "value": "Reported to Red Hat."
                    },
                    {
                        "lang": "en",
                        "time": "2026-04-14T16:57:53.069Z",
                        "value": "Made public."
                    }
                ],
                "title": "dotnet: .NET Framework: Denial of Service via Race Condition",
                "x_adpType": "supplier",
                "x_generator": {
                    "engine": "sadp-cli 1.0.0"
                },
                "providerMetadata": {
                    "orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
                    "shortName": "redhat-SADP",
                    "dateUpdated": "2026-07-15T01:18:11.295Z"
                }
            }
        ]
    }
}