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        "state": "PUBLISHED",
        "assignerShortName": "NLnet Labs",
        "dateReserved": "2026-06-22T10:11:10.518Z",
        "datePublished": "2026-07-22T13:04:52.605Z",
        "dateUpdated": "2026-07-22T14:29:25.088Z"
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            "title": "Degradation of resolution service from improperly accounted client-terminated DNS-over-QUIC queries",
            "datePublic": "2026-07-22T00:00:00.000Z",
            "affected": [
                {
                    "vendor": "NLnet Labs",
                    "product": "Unbound",
                    "versions": [
                        {
                            "version": "1.22.0",
                            "status": "affected",
                            "lessThan": "1.25.2",
                            "versionType": "semver"
                        }
                    ],
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            "descriptions": [
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                    "lang": "en",
                    "value": "In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, client terminated DNS-over-QUIC (DoQ) queries are not accounted properly by Unbound resulting in low-cost inflation of the waiting number of replies for already in-flight resolution queries. This results in degradation of resolution service for new clients for already in-flight queries. A malicious actor can exploit the vulnerability by issuing DoQ queries for query names that need resolution and proceeding on immediately terminating the query by one of STOP_SENDING/RESET_STREAM/CONNECTION_CLOSE QUIC frames. Those terminated DoQ queries are not properly counted for and keep inflating the number of waiting replies for in-flight queries. When the maximum is reached, it results in silent query drops for new clients needing resolution for already in-flight queries. This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces. Additionally, a malicious actor needs access to multiple source IPs to bypass the by-default configured 'wait-limit' option."
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                            "value": "Unbound compiled with DoQ support ('--with-libngtcp2')"
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                        "baseScore": 3.7,
                        "baseSeverity": "LOW",
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                            "cweId": "CWE-772",
                            "description": "CWE-772: Missing Release of Resource after Effective Lifetime",
                            "type": "CWE"
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            ],
            "solutions": [
                {
                    "lang": "en",
                    "value": "This issue is fixed starting with version 1.25.2"
                }
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            "timeline": [
                {
                    "time": "2026-05-22T00:00:00.000Z",
                    "lang": "en",
                    "value": "Issue reported by Qifan Zhang"
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                {
                    "time": "2026-06-17T00:00:00.000Z",
                    "lang": "en",
                    "value": "NLnet Labs shares patch"
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                {
                    "time": "2026-06-17T00:00:00.000Z",
                    "lang": "en",
                    "value": "Qifan Zhang verifies patch"
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                {
                    "time": "2026-07-22T00:00:00.000Z",
                    "lang": "en",
                    "value": "Fixes released with version 1.25.2"
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            "credits": [
                {
                    "lang": "en",
                    "value": "Qifan Zhang (Palo Alto Networks)",
                    "type": "finder"
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            "references": [
                {
                    "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-41637.txt",
                    "tags": [
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