{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-5950",
        "assignerOrgId": "404fd4d2-a609-4245-b543-2c944a302a22",
        "state": "PUBLISHED",
        "assignerShortName": "isc",
        "dateReserved": "2026-04-09T06:42:23.953Z",
        "datePublished": "2026-05-20T13:10:19.989Z",
        "dateUpdated": "2026-05-20T13:38:53.211Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "404fd4d2-a609-4245-b543-2c944a302a22",
                "shortName": "isc",
                "dateUpdated": "2026-05-20T13:10:19.989Z"
            },
            "title": "Unbounded resend loop in BIND 9 resolver",
            "datePublic": "2026-05-20T00:00:00.000Z",
            "affected": [
                {
                    "vendor": "ISC",
                    "product": "BIND 9",
                    "versions": [
                        {
                            "version": "9.18.36",
                            "lessThanOrEqual": "9.18.48",
                            "status": "affected",
                            "versionType": "custom"
                        },
                        {
                            "version": "9.20.8",
                            "lessThanOrEqual": "9.20.22",
                            "status": "affected",
                            "versionType": "custom"
                        },
                        {
                            "version": "9.21.7",
                            "lessThanOrEqual": "9.21.21",
                            "status": "affected",
                            "versionType": "custom"
                        },
                        {
                            "version": "9.18.36-S1",
                            "lessThanOrEqual": "9.18.48-S1",
                            "status": "affected",
                            "versionType": "custom"
                        },
                        {
                            "version": "9.20.9-S1",
                            "lessThanOrEqual": "9.20.22-S1",
                            "status": "affected",
                            "versionType": "custom"
                        }
                    ],
                    "defaultStatus": "unaffected"
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "9.18.36",
                                    "versionEndIncluding": "9.18.48"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "9.20.8",
                                    "versionEndIncluding": "9.20.22"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "9.21.7",
                                    "versionEndIncluding": "9.21.21"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "9.18.36-S1",
                                    "versionEndIncluding": "9.18.48-S1"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "9.20.9-S1",
                                    "versionEndIncluding": "9.20.22-S1"
                                }
                            ]
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
                        "availabilityImpact": "LOW",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
                        "baseScore": 5.3,
                        "baseSeverity": "MEDIUM"
                    }
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "type": "CWE",
                            "cweId": "CWE-606",
                            "description": "CWE-606 Unchecked Input for Loop Condition"
                        }
                    ]
                }
            ],
            "descriptions": [
                {
                    "lang": "en",
                    "value": "An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during bad-server handling, enabling a remote unauthenticated attacker to cause severe resource exhaustion by sending queries that trigger specific retry conditions.\nThis issue affects BIND 9 versions 9.18.36 through 9.18.48, 9.20.8 through 9.20.22, 9.21.7 through 9.21.21, 9.18.36-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1."
                }
            ],
            "impacts": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "value": "Severe resource exhaustion."
                        }
                    ]
                }
            ],
            "workarounds": [
                {
                    "lang": "en",
                    "value": "No workarounds known."
                }
            ],
            "exploits": [
                {
                    "lang": "en",
                    "value": "We are not aware of any active exploits."
                }
            ],
            "solutions": [
                {
                    "lang": "en",
                    "value": "Upgrade to the patched release most closely related to your current version of BIND 9: 9.18.49, 9.20.23, 9.21.22, 9.18.49-S1, or 9.20.23-S1."
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "ISC would like to thank Billy Baraja (BielraX) for bringing this vulnerability to our attention."
                }
            ],
            "references": [
                {
                    "url": "https://kb.isc.org/docs/cve-2026-5950",
                    "name": "CVE-2026-5950",
                    "tags": [
                        "vendor-advisory"
                    ]
                },
                {
                    "url": "https://downloads.isc.org/isc/bind9/9.18.49",
                    "tags": [
                        "patch"
                    ]
                },
                {
                    "url": "https://downloads.isc.org/isc/bind9/9.20.23",
                    "tags": [
                        "patch"
                    ]
                },
                {
                    "url": "https://downloads.isc.org/isc/bind9/9.21.22",
                    "tags": [
                        "patch"
                    ]
                }
            ],
            "source": {
                "discovery": "EXTERNAL"
            },
            "x_generator": {
                "engine": "cvelib 1.8.0"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-05-20T13:38:40.421994Z",
                                "id": "CVE-2026-5950",
                                "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": "2026-05-20T13:38:53.211Z"
                }
            }
        ]
    }
}