{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-32665", "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6", "state": "PUBLISHED", "assignerShortName": "NLnet Labs", "dateReserved": "2026-05-07T10:07:51.860Z", "datePublished": "2026-07-22T13:04:18.594Z", "dateUpdated": "2026-07-22T14:32:02.752Z"}, "containers": {"cna": {"title": "Remote DNS-over-QUIC denial of service due to `quic-size` budget bypass", "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"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, when downstream DNS-over-QUIC (DoQ) is enabled, the first two bidirectional streams on a new QUIC connection (stream_id 0 and 4) bypass the per-stream 'quic-size' gate entirely, and large input buffers are allocated later, after only the 2-byte length prefix has been received from the initial streams. As a result, a remote client can make Unbound exceed the configured 'quic-size' limit with low-cost input. Using only one connection and two streams, each sending a declared 65535-byte length prefix and then holding the streams open, a client can already trivially make Unbound roughly allocate double that amount. This is a remote availability issue / memory-accounting bypass in the downstream DoQ implementation that leads to denial of service for new DoQ clients. This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces."}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "Unbound compiled with DoQ support ('--with-libngtcp2')"}], "cvssV3_1": {"version": "3.1", "baseScore": 7.5, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}}], "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-1284", "description": "CWE-1284: Improper Validation of Specified Quantity in Input", "type": "CWE"}]}], "solutions": [{"lang": "en", "value": "This issue is fixed starting with version 1.25.2"}], "timeline": [{"time": "2026-04-01T00:00:00.000Z", "lang": "en", "value": "Issue reported by N0zoM1z0"}, {"time": "2026-04-03T00:00:00.000Z", "lang": "en", "value": "NLnet Labs shares patch with N0zoM1z0"}, {"time": "2026-04-03T00:00:00.000Z", "lang": "en", "value": "N0zoM1z0 verifies patch"}, {"time": "2026-04-03T00:00:00.000Z", "lang": "en", "value": "Issue reported by Kunta Chu"}, {"time": "2026-04-09T00:00:00.000Z", "lang": "en", "value": "NLnet Labs shares patch with Kunta Chu"}, {"time": "2026-04-03T00:00:00.000Z", "lang": "en", "value": "Kunta Chu verifies patch"}, {"time": "2026-05-30T00:00:00.000Z", "lang": "en", "value": "Issue reported by Qifan Zhang"}, {"time": "2026-06-15T00:00:00.000Z", "lang": "en", "value": "NLnet Labs shares patch with Qifan Zhang"}, {"time": "2026-06-17T00:00:00.000Z", "lang": "en", "value": "Qifan Zhang verifies patch"}, {"time": "2026-07-10T00:00:00.000Z", "lang": "en", "value": "Issue reported by Xuanchao Xie"}, {"time": "2026-07-10T00:00:00.000Z", "lang": "en", "value": "NLnet Labs shares patch with Xuanchao Xie"}, {"time": "2026-07-11T00:00:00.000Z", "lang": "en", "value": "Xuanchao Xie verifies patch"}, {"time": "2026-07-22T00:00:00.000Z", "lang": "en", "value": "Fixes released with version 1.25.2"}], "credits": [{"lang": "en", "value": "N0zoM1z0 (GitHub user)", "type": "finder"}, {"lang": "en", "value": "Kunta Chu (Tsinghua University)", "type": "finder"}, {"lang": "en", "value": "Kaihua Wang (Tsinghua University)", "type": "finder"}, {"lang": "en", "value": "Jianjun Chen (Tsinghua University)", "type": "finder"}, {"lang": "en", "value": "Qifan Zhang (Palo Alto Networks)", "type": "finder"}, {"lang": "en", "value": "Xuanchao Xie", "type": "finder"}], "references": [{"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-32665.txt", "tags": ["vendor-advisory"]}], "providerMetadata": {"orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6", "shortName": "NLnet Labs", "dateUpdated": "2026-07-22T13:04:18.594Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-07-22T14:31:54.691586Z", "id": "CVE-2026-32665", "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": "2026-07-22T14:32:02.752Z"}}]}}

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