{"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"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-32665", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-22T14:31:54.691586Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-22T14:31:59.156Z"}}], "cna": {"title": "Remote DNS-over-QUIC denial of service due to `quic-size` budget bypass", "credits": [{"lang": "en", "type": "finder", "value": "N0zoM1z0 (GitHub user)"}, {"lang": "en", "type": "finder", "value": "Kunta Chu (Tsinghua University)"}, {"lang": "en", "type": "finder", "value": "Kaihua Wang (Tsinghua University)"}, {"lang": "en", "type": "finder", "value": "Jianjun Chen (Tsinghua University)"}, {"lang": "en", "type": "finder", "value": "Qifan Zhang (Palo Alto Networks)"}, {"lang": "en", "type": "finder", "value": "Xuanchao Xie"}], "metrics": [{"format": "CVSS", "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"}, "scenarios": [{"lang": "en", "value": "Unbound compiled with DoQ support ('--with-libngtcp2')"}]}], "affected": [{"vendor": "NLnet Labs", "product": "Unbound", "versions": [{"status": "affected", "version": "1.22.0", "lessThan": "1.25.2", "versionType": "semver"}], "defaultStatus": "unaffected"}], "timeline": [{"lang": "en", "time": "2026-04-01T00:00:00.000Z", "value": "Issue reported by N0zoM1z0"}, {"lang": "en", "time": "2026-04-03T00:00:00.000Z", "value": "NLnet Labs shares patch with N0zoM1z0"}, {"lang": "en", "time": "2026-04-03T00:00:00.000Z", "value": "N0zoM1z0 verifies patch"}, {"lang": "en", "time": "2026-04-03T00:00:00.000Z", "value": "Issue reported by Kunta Chu"}, {"lang": "en", "time": "2026-04-09T00:00:00.000Z", "value": "NLnet Labs shares patch with Kunta Chu"}, {"lang": "en", "time": "2026-04-03T00:00:00.000Z", "value": "Kunta Chu verifies patch"}, {"lang": "en", "time": "2026-05-30T00:00:00.000Z", "value": "Issue reported by Qifan Zhang"}, {"lang": "en", "time": "2026-06-15T00:00:00.000Z", "value": "NLnet Labs shares patch with Qifan Zhang"}, {"lang": "en", "time": "2026-06-17T00:00:00.000Z", "value": "Qifan Zhang verifies patch"}, {"lang": "en", "time": "2026-07-10T00:00:00.000Z", "value": "Issue reported by Xuanchao Xie"}, {"lang": "en", "time": "2026-07-10T00:00:00.000Z", "value": "NLnet Labs shares patch with Xuanchao Xie"}, {"lang": "en", "time": "2026-07-11T00:00:00.000Z", "value": "Xuanchao Xie verifies patch"}, {"lang": "en", "time": "2026-07-22T00:00:00.000Z", "value": "Fixes released with version 1.25.2"}], "solutions": [{"lang": "en", "value": "This issue is fixed starting with version 1.25.2"}], "datePublic": "2026-07-22T00:00:00.000Z", "references": [{"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-32665.txt", "tags": ["vendor-advisory"]}], "x_generator": {"engine": "cvelib 1.8.0"}, "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-1284", "description": "CWE-1284: Improper Validation of Specified Quantity in Input"}]}], "providerMetadata": {"orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6", "shortName": "NLnet Labs", "dateUpdated": "2026-07-22T13:04:18.594Z"}}}, "cveMetadata": {"cveId": "CVE-2026-32665", "state": "PUBLISHED", "dateUpdated": "2026-07-22T14:32:02.752Z", "dateReserved": "2026-05-07T10:07:51.860Z", "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6", "datePublished": "2026-07-22T13:04:18.594Z", "assignerShortName": "NLnet Labs"}, "dataVersion": "5.2"}

{}

{"affected_release": [{"advisory": "RHSA-2026:43588", "cpe": "cpe:/a:redhat:hummingbird:1", "impact": "important", "package": "unbound-main-1.25.2-0.1.hum1", "product_name": "Red Hat Hardened Images", "release_date": "2026-07-22T00:00:00Z"}], "bugzilla": {"description": "unbound: Unbound: Denial of Service via improper validation of DNS-over-QUIC client length", "id": "2503060", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2503060"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "verified"}, "cwe": "CWE-770", "details": ["A flaw was found in Unbound when DNS-over-QUIC (DoQ) is enabled. An attacker could exploit improper validation of client-provided data length, leading to excessive memory allocation. This can cause the system to exceed its configured memory limits for QUIC connections, resulting in a Denial of Service (DoS) for new DoQ clients."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, disable DNS-over-QUIC (DoQ) in the Unbound configuration if it is not a required service. This can typically be achieved by commenting out or removing DoQ-related configuration options in `unbound.conf`. For example, remove or comment out lines such as `do-quic: yes` or `quic-port: 853`.\nAfter modifying the configuration, restart the Unbound service for the changes to take effect:\n```bash\nsystemctl restart unbound\n```\nWarning: Restarting the Unbound service will temporarily interrupt DNS resolution."}, "name": "CVE-2026-32665", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-07-22T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-32665\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-32665"], "statement": "This Important flaw in Unbound, when configured for DNS-over-QUIC (DoQ), can lead to a denial of service for new DoQ clients. An attacker can exploit improper validation of client-provided data length, causing excessive memory allocation and exceeding configured limits. This impacts the availability of the DNS resolver for DoQ connections.", "threat_severity": "Important"}