{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-42944", "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6", "state": "PUBLISHED", "assignerShortName": "NLnet Labs", "dateReserved": "2026-05-07T10:07:51.833Z", "datePublished": "2026-05-20T09:20:23.906Z", "dateUpdated": "2026-05-20T13:38:17.529Z"}, "containers": {"cna": {"title": "Heap overflow with multiple NSID, COOKIE, PADDING EDNS options", "datePublic": "2026-05-20T00:00:00.000Z", "affected": [{"vendor": "NLnet Labs", "product": "Unbound", "versions": [{"version": "1.14.0", "status": "affected", "lessThan": "1.25.1", "versionType": "semver"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation."}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"version": "4.0", "baseScore": 8.7, "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Red"}}], "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-197", "description": "CWE-197: Numeric Truncation Error", "type": "CWE"}, {"lang": "en", "cweId": "CWE-787", "description": "CWE-787: Out-of-bounds Write", "type": "CWE"}]}], "solutions": [{"lang": "en", "value": "This issue is fixed starting with version 1.25.1"}], "timeline": [{"time": "2026-04-26T00:00:00.000Z", "lang": "en", "value": "Issue reported by Qifan Zhang"}, {"time": "2026-04-28T00:00:00.000Z", "lang": "en", "value": "NLnet Labs shares patch"}, {"time": "2026-04-29T00:00:00.000Z", "lang": "en", "value": "Qifan Zhang verifies patch"}, {"time": "2026-05-20T00:00:00.000Z", "lang": "en", "value": "Fixes released with version 1.25.1"}], "credits": [{"lang": "en", "value": "Qifan Zhang (Palo Alto Networks)", "type": "finder"}], "references": [{"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-42944.txt", "tags": ["vendor-advisory"]}], "providerMetadata": {"orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6", "shortName": "NLnet Labs", "dateUpdated": "2026-05-20T09:20:23.906Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-05-20T13:37:32.347565Z", "id": "CVE-2026-42944", "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": "2026-05-20T13:38:17.529Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-42944", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-05-20T13:37:32.347565Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-05-20T13:37:37.199Z"}}], "cna": {"title": "Heap overflow with multiple NSID, COOKIE, PADDING EDNS options", "credits": [{"lang": "en", "type": "finder", "value": "Qifan Zhang (Palo Alto Networks)"}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "baseScore": 8.7, "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Red"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"vendor": "NLnet Labs", "product": "Unbound", "versions": [{"status": "affected", "version": "1.14.0", "lessThan": "1.25.1", "versionType": "semver"}], "defaultStatus": "unaffected"}], "timeline": [{"lang": "en", "time": "2026-04-26T00:00:00.000Z", "value": "Issue reported by Qifan Zhang"}, {"lang": "en", "time": "2026-04-28T00:00:00.000Z", "value": "NLnet Labs shares patch"}, {"lang": "en", "time": "2026-04-29T00:00:00.000Z", "value": "Qifan Zhang verifies patch"}, {"lang": "en", "time": "2026-05-20T00:00:00.000Z", "value": "Fixes released with version 1.25.1"}], "solutions": [{"lang": "en", "value": "This issue is fixed starting with version 1.25.1"}], "datePublic": "2026-05-20T00:00:00.000Z", "references": [{"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-42944.txt", "tags": ["vendor-advisory"]}], "x_generator": {"engine": "cvelib 1.8.0"}, "descriptions": [{"lang": "en", "value": "NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-197", "description": "CWE-197: Numeric Truncation Error"}, {"lang": "en", "type": "CWE", "cweId": "CWE-787", "description": "CWE-787: Out-of-bounds Write"}]}], "providerMetadata": {"orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6", "shortName": "NLnet Labs", "dateUpdated": "2026-05-20T09:20:23.906Z"}}}, "cveMetadata": {"cveId": "CVE-2026-42944", "state": "PUBLISHED", "dateUpdated": "2026-05-20T13:38:17.529Z", "dateReserved": "2026-05-07T10:07:51.833Z", "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6", "datePublished": "2026-05-20T09:20:23.906Z", "assignerShortName": "NLnet Labs"}, "dataVersion": "5.2"}

{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*", "matchCriteriaId": "94679303-2382-42F1-8BFF-FD02D0444EE6", "versionEndExcluding": "1.25.1", "versionStartIncluding": "1.14.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation."}], "id": "CVE-2026-42944", "lastModified": "2026-05-20T22:50:49.877", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.7, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "RED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Red", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "sep@nlnetlabs.nl", "type": "Secondary"}]}, "published": "2026-05-20T10:16:27.760", "references": [{"source": "sep@nlnetlabs.nl", "tags": ["Mitigation", "Vendor Advisory"], "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-42944.txt"}], "sourceIdentifier": "sep@nlnetlabs.nl", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-197"}, {"lang": "en", "value": "CWE-787"}], "source": "sep@nlnetlabs.nl", "type": "Secondary"}]}

{}

{"created": "2026-05-20T11:30:26.138943+00:00", "updated": "2026-05-20T11:30:26.138957+00:00", "vendors": []}