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    "cveMetadata": {
        "cveId": "CVE-2026-44621",
        "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
        "state": "PUBLISHED",
        "assignerShortName": "NLnet Labs",
        "dateReserved": "2026-06-22T10:11:10.524Z",
        "datePublished": "2026-07-22T13:06:28.947Z",
        "dateUpdated": "2026-07-22T14:21:22.388Z"
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    "containers": {
        "cna": {
            "title": "Libunbound applications configured with 'unwanted-reply-threshold' could eventually be abruptly terminated",
            "datePublic": "2026-07-22T00:00:00.000Z",
            "affected": [
                {
                    "vendor": "NLnet Labs",
                    "product": "Unbound",
                    "versions": [
                        {
                            "version": "0",
                            "status": "affected",
                            "lessThan": "1.25.2",
                            "versionType": "semver"
                        }
                    ],
                    "defaultStatus": "unaffected"
                }
            ],
            "descriptions": [
                {
                    "lang": "en",
                    "value": "With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and libunbound needs to call 'libworker_alloc_cleanup' since the function is absent from the function call allow list. When an application using libunbound sets 'unwanted-reply-threshold' to any non-zero value and the iterator queries an authoritative that replies with enough wrong-transaction-ID UDP datagrams to cross the threshold, the 'libworker_alloc_cleanup' will eventually be called. Since the function is absent from the function call allow list, this leads to a fatal exit of libunbound and eventual termination of the embedding application.Unbound itself is not affected since its relevant function 'worker_alloc_cleanup' is registed in the allow list and proceeds to perform the documented cache flush."
                }
            ],
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                    "format": "CVSS",
                    "scenarios": [
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                            "lang": "en",
                            "value": "Libunbound applications"
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                    ],
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                        "version": "3.1",
                        "baseScore": 5.9,
                        "baseSeverity": "MEDIUM",
                        "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
                    }
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "cweId": "CWE-754",
                            "description": "CWE-754: Improper Check for Unusual or Exceptional Conditions",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "solutions": [
                {
                    "lang": "en",
                    "value": "This issue is fixed starting with version 1.25.2"
                }
            ],
            "timeline": [
                {
                    "time": "2026-05-18T00:00:00.000Z",
                    "lang": "en",
                    "value": "Issue reported by Qifan Zhang"
                },
                {
                    "time": "2026-06-10T00:00:00.000Z",
                    "lang": "en",
                    "value": "NLnet Labs shares patch"
                },
                {
                    "time": "2026-06-13T00:00:00.000Z",
                    "lang": "en",
                    "value": "Qifan Zhang verifies patch"
                },
                {
                    "time": "2026-07-22T00:00:00.000Z",
                    "lang": "en",
                    "value": "Fixes released with version 1.25.2"
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "Qifan Zhang (Palo Alto Networks)",
                    "type": "finder"
                }
            ],
            "references": [
                {
                    "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-44621.txt",
                    "tags": [
                        "vendor-advisory"
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
                "shortName": "NLnet Labs",
                "dateUpdated": "2026-07-22T13:06:28.947Z"
            },
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                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-07-22T14:21:13.870660Z",
                                "id": "CVE-2026-44621",
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                                        "Exploitation": "none"
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