CVE-2026-32665

{"id": "CVE-2026-32665", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-32665", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-22T14:31:54.691586Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "sep@nlnetlabs.nl", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}]}, "affected": [{"source": "sep@nlnetlabs.nl", "affectedData": [{"vendor": "NLnet Labs", "product": "Unbound", "versions": [{"status": "affected", "version": "1.22.0", "lessThan": "1.25.2", "versionType": "semver"}], "defaultStatus": "unaffected"}]}], "published": "2026-07-22T14:17:18.193", "references": [{"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-32665.txt", "tags": ["Vendor Advisory"], "source": "sep@nlnetlabs.nl"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "sep@nlnetlabs.nl", "description": [{"lang": "en", "value": "CWE-1284"}]}], "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."}, {"lang": "es", "value": "En NLnet Labs Unbound 1.22.0 hasta la versi\u00f3n 1.25.1 inclusive, cuando DNS-over-QUIC (DoQ) descendente est\u00e1 habilitado, los dos primeros flujos bidireccionales en una nueva conexi\u00f3n QUIC (stream_id 0 y 4) omiten completamente la \u2019puerta\u2019 \u2019quic-size\u2019 por flujo, y se asignan grandes b\u00faferes de entrada m\u00e1s tarde, despu\u00e9s de que solo se haya recibido el prefijo de longitud de 2 bytes de los flujos iniciales. Como resultado, un cliente remoto puede hacer que Unbound exceda el l\u00edmite \u2019quic-size\u2019 configurado con entrada de bajo costo. Usando solo una conexi\u00f3n y dos flujos, cada uno enviando un prefijo de longitud declarado de 65535 bytes y luego manteniendo los flujos abiertos, un cliente ya puede hacer que Unbound asigne aproximadamente el doble de esa cantidad de forma trivial. Esto es un problema de disponibilidad remota / una omisi\u00f3n de contabilidad de memoria en la implementaci\u00f3n descendente de DoQ que conduce a la denegaci\u00f3n de servicio para nuevos clientes DoQ. Esta vulnerabilidad requiere que Unbound sea compilado con soporte DoQ (\u2019--with-libngtcp2\u2019) y que el puerto \u2019quic-port\u2019 sea configurado para las interfaces de escucha."}], "lastModified": "2026-10-24T13:10:00.147", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0C48102E-1D81-4A87-898D-F1CE83C78D26", "versionEndExcluding": "1.25.2", "versionStartIncluding": "1.22.0"}], "operator": "OR"}]}], "sourceIdentifier": "sep@nlnetlabs.nl"}